Overview
Your joints and muscles have a certain range of motion that the body allows. Flexibility is the ability of the body to move freely through this allowed range. Flexibility is also known as limberness. The parts engaged more while moving are usually more flexible than those that are not put to much use.
Some people are more flexible than others. Genetics play a role in determining how flexible your joints and muscles are. Exercise can also improve a person’s flexibility to a certain extent.
There are two types of flexibility.
Dynamic flexibility - The ability to move joints to the maximum of their allowed range of motion (e.g., bending down to pick up an item or stretching to take something from a higher shelf).
Static flexibility - The ability to maintain a position for a longer time without any external support (e.g., lifting your leg and keeping it high without holding any support).
Importance Of Flexibility
Reduced Injury Risk
When you have higher flexibility, your body can handle physical stress much better. Hence, when you are exercising or doing a strenuous physical activity, the chances of getting hurt are lesser.
Improved Balance and Posture
A study concluded that people who take up flexibility exercises and stretching two times a week for 12 weeks saw improved balance and lumbar strength.
Improved Athletic Performance
A study that explored the effects of yoga on athletes reported that yoga improved flexibility in adult athletes. Flexibility, in turn, improved athletic performance.
Lesser Body Pain
When your body is more flexible, the muscles are better relaxed. This reduces general body pain in adults and children.
Reduced Risk of Heart Diseases
A 2009 article relates poor trunk flexibility to increased risks of arterial stiffening. Arterial stiffening is the stiffening and thickening of the artery walls that can lead to heart diseases.
Is Flexibility Genetic?
The Influence of ACTN3 Gene on Flexibility
The ACTN3 gene helps produce the Alpha-actinin protein. This protein gives structure to muscles in the body.
A 2014 study analyzed the effects of polymorphism of the ACTN3 gene in flexibility and injury risk in ballet dancers in Korea.
The result concluded that those ballerinas with the ACTN3 TT genotype of the rs1815739 SNP are less flexible than others and have higher risks for ankle-joint injuries. Ballerinas with the CT and CC genotype were more flexible and hence had lesser risks for injuries.
The Influence of COL5A1 Gene on Flexibility
The COL5A1 gene is called the ‘flexibility gene.’ This helps produce the type V collagen. Collagen helps in strengthening your bones, muscles, skin, and tendons. It keeps your joints mobile and flexible. Lowered levels of collagen can result in stiffness and reduced flexibility.
rs12722 is an SNP of the COL5A1 gene. The T allele of this SNP causes quadricep stiffness and an increased risk of muscle injuries while the C allele is not associated with flexibility issues.
Ehlers-Danlos Syndrome
Ehlers-Danlos Syndrome (EDS) is a genetic disorder that results in loose joints, very stretchy skin, and overly flexible joints. People with the syndrome have extra ranges of joint movements, also called hypermobility. EDS can cause joint pain, frequent injuries, and bruises in the skin.
More than 100 different mutations in the COL5A1 gene are noted in people with EDS.
Non-genetic Factors Affecting Flexibility
Age - Newborns are extremely flexible. Flexibility in the body reduces as you age. After 55 years of age, collagen production reduces, and tissues start losing water. This brings down flexibility levels.
Body Bulk - If you have more bulky, it may be difficult to stretch or move limbs and muscles.
Gender - Women are considered more flexible than men.
The temperature and time of the day - You might be surprised, but your body’s flexibility depends on what time of the day it is and the external temperature. Warmer climates improve flexibility, and people are more flexible in the afternoons than in the mornings.
Over-flexibility - Is It a Problem?
Over-flexibility is a problem when your muscles, ligaments, and tendons stretch beyond what’s normal for them. It puts stress on your tendons and ligaments and results in injuries.
Ligaments are not to be stretched more than 6% of their length. Some people can be over flexible because of their genes, which increases their risks of injuries and ligament tear.
Recommendations To Improve Flexibility
Exercise Right
Yoga, stretching exercises, pilates, etc., are all different kinds of exercises that help improve your flexibility. All these exercises gently stretch muscles and improve mobility.
Practice Static Flexible Exercises
Static flexible exercises require you to hold a stretch or a position for 30 -60 seconds before relaxing. Static flexible exercises help improve flexibility.
Relax Your Muscles
Taking a warm water bath can instantly relax your muscles and improve your flexibility.
Professional massages
When done right, massages can help improve flexibility and your range of motion, keeping your joints stronger and agile.
Hydration
Water is essential for the normal functioning of the body. Dehydration can cause inflexibility and limit your range of motion. Make sure you drink adequate water to improve flexibility.
Stay Stress-free
Stress is known to tighten muscles and decrease physical flexibility. Working on mental stress levels can help the muscles relax and improve your flexibility levels.
Summary
- Flexibility is the range of motion that your joints and muscles have. There are two types of flexibility, namely, dynamic and static flexibility.
- Flexibility depends on genetics and other factors like age, body bulk, and physical fitness.
- Flexing and stretching muscles, tendons, and ligaments beyond their capacities can cause injuries.
- Some genes are known to play a role in flexibility levels. Changes in the ACTN3 and COL5A1 genes can increase/decrease flexibility and may make you more susceptible to injuries.
- Practicing certain forms of exercise, keeping the body hydrated, and staying relaxed can improve flexibility.
References
https://www.frontiersin.org/articles/10.3389/fphys.2017.01080/full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4241924/
https://medlineplus.gov/genetics/gene/col5a1/#conditions
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4523805/
https://physoc.onlinelibrary.wiley.com/doi/10.1113/EP085974
https://sites.psu.edu/kinescfw/health-education/exercise-articles/the-importance-of-flexibility-and-mobility/
https://www.sciencedirect.com/science/article/pii/S0002929707635290
About Xcode Life's Gene Fitness Report
Update on 16th January, 2021
Abstract
ACTN3, popularly called the Speed Gene, is responsible for the production of α-actinin-3, a protein expressed in fast-firing skeletal muscle fibers. This protein is deficient in approximately 1.5 billion people worldwide.
Previous studies indicate that α-actinin-3 is associated with muscle function, and an α-actinin-3 deficiency adversely affects performance in speed and power activities. Recent research suggests that α-actinin-3 deficiency generates heat in the body (thermogenesis), and as a result, α-actinin-3 deficient humans adapt better to lower temperatures.
What Is -actinin-3?
The α-actinin-3 protein was first identified during research into muscular dystrophy defects. Further studies showed that a deficiency of α-actinin-3 was common- roughly 18% of the world population has an ACTN3 deficiency mutation. This deficiency correlates with the following factors:
- Athletic performance
- Greater altitude and lower temperatures
- Evolutionary selection
A previous study exploring the evolutionary implications of α-actinin-3 deficiency indicated that a version of the ACTN3 gene became more abundant as humans migrated out of Africa into the colder climates of Northern and Central Europe.
Studies also suggest that an X derivative of the ACTN3 gene is overexpressed among marathoners and endurance athletes but underexpressed in sprinters. The X derivative indicates an incomplete ACTN3 gene and is thereby associated with α-actinin-3 deficiency.
In general, an α-actinin-3 deficiency is detrimental for sprint and power activities. Evolutionary evidence also indicates a strong positive selection of the X derivative of the ACTN3 gene in European and East Asian populations. Positive selection is the process by which the "advantageous" changes or gene variants are passed on consistently in a population.
Loss of α-actinin-3 and Better Cold Resilience
A study conducted by a team of researchers examined the mechanism responsible for the positive selection of the X derivative of the ACTN3 gene. It aimed to understand the thermogenic role of skeletal muscle during cold exposure in humans.
The study was conducted on the following two groups: Healthy males aged 18 to 40 years, residing in Kaunas, Lithuania. They followed moderate physical activity and had no exposure to an extreme temperature for at least three months prior to the study. Thirteen age-matched 3-month-old wild-type mice and mice with inactivated ACTN3 genes, housed in a specific-pathogen-free environment. They were maintained at a constant ambient temperature of 22°C and 50% humidity on a 12 h light-dark cycle, with limited access to food and water.
The following parameters were measured in humans:
- Weight (in kg)
- Body fat percentage
- Height (in cm)
- Skinfold thickness (in mm)
Based on the above parameters, the following were calculated:
- Body mass index
- Body surface area (in m2)
- Mean subcutaneous fat layer thickness
Coldwater exposure was conducted as follows:
- Humans were subjected to an intermittent whole body cold-water immersion
- Mice were exposed to acute temperature exposure treatments
The following parameters were examined in both humans and mice:
- Collection of genes
- Body temperature measurements
- Heart rate
- Oxygen intake and Carbon-dioxide output
- Signal measurement associated with heat-generating muscle activation
Apart from these, protein analyses in humans and RNA sequencing in mice were performed, and the data obtained were statistically analyzed.
The Results of the Study
The study observed that the percentage of individuals able to maintain their body temperature above 35.5°C during the cold-water exposure was higher in the ACTN3 deficient (XX) group than the ACTN3 efficient (RR) group. However, there was a significant overall increase in energy consumption induced by the cold irrespective of the ACTN3 gene status. This implies that α-actinin-3-deficient individuals exhibit superior protection of core body temperature during cold exposure without a corresponding increase in energy consumption.
Researchers suggest a physiological mechanism underlying the energy-efficient cold protection in XX individuals. Mammals regulate their body temperature when exposed to acute cold temperatures through involuntary muscle contraction. This is colloquially referred to as shivering - this activity was twice as high in RR individuals as in XX individuals. In individuals with the X derivative, these contractions most likely happen in slow twitch-type muscles with a heat-generating increase in muscle tone. This conserves more energy when compared to shivering.
The X derivative of the ACTN3 gene occurs more commonly in people living in colder climates, indicating an evolutionary survival advantage of α-actinin-3 deficiency as humans migrated to colder places.
In conclusion, α-actinin-3-deficient humans use a more energy-efficient mechanism of generating body heat, thereby exhibiting improved cold tolerance.
Recommendations to Improve Cold Resilience
- Take cold showers to acclimate your body to the cold
- Avoid wearing too many layers of clothes when you feel cold
- Spend more time in cold temperatures
- Exercise regularly and improve body metabolism
- Drink cold water or cold beverages
Summary
- α-actinin-3, a protein expressed in fast-twitch skeletal muscle, is commonly deficient in humans.
- This deficiency is associated with:
- Athletic performance
- Greater altitude and lower temperatures
- Evolutionary selection
- A study conducted by a team of researchers explored the thermogenic role of α-actinin-3 deficiency during cold exposure in humans.
- The study found that α-actinin-3-deficient individuals exhibited superior protection of core body temperature during cold exposure without any increase in energy consumption when compared to α-actinin-3-efficient individuals.
Xcode Life’s Gene Fitness report analyzes genes associated with your physical fitness, sports performance, and athletic ability. The report can help modify your fitness training according to your genetic type for better results.
Genetics and Fitness
Genetics is becoming more popular in the field of sports and fitness. Professional sports teams around the world are beginning to incorporate genetics in their fitness regime. Research shows that your efficiency in performing certain physical activities is linked to your genes.
Gene Fitness Report
The Gene Fitness Report profiles genes that have been shown to influence endurance, performance, aerobic capacity, power, strength, and other attributes related to fitness.
The Key Takeaways section of the report highlights how you are likely to respond to power and endurance exercises. Based on your genetic type, you will also find a personalized exercise plan, including the frequency, duration, intensity, and type of exercise that would best suit you.

The Summary Table in the report indicates your outcome for each trait.

Along with your outcome, the details of the genes analyzed for each trait are also provided. The report comes with personalized recommendations based on your results. These recommendations are to be followed only after consulting a trained fitness professional. You can click on “Learn More” for more information on each trait.
What are the traits covered in this report?
The report analyzes genes associated with 16 fitness traits which include, power, flexibility, exercise motivation, the likelihood of injury, and weight loss or weight gain with exercise. For a comprehensive list of the traits covered, click here.
Power, also known as skeletal muscle power, is defined in fitness and sports as the ability to exert maximum force in minimum time. With improved power, a person can exhibit skills and perform the movement with maximum force in a short period of time. Power is often confused with strength. They are actually quite different. Strength is your capacity to do a particular exercise, which is basically the maximum force you can apply against a load. Power takes into account both strength and speed.
Muscle power is an important aspect of fitness and sports training, and athletics. In weight lifting, boxing, and similar sports, muscle power is the major physical attribute that plays a role in the person’s performance. Even in everyday life, power increases your ability to do activities like lifting boxes, opening doors, or other intensive activities without too much strain.
Why is Power Important?
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Strengthens bone and muscle:
As you grow older, your muscle power tends to decrease faster than your strength. Power training is a great way to keep your muscles and bones in check as you age. -
More blood pumping and healthier heart:
Power training is known to enhance your heart function by increasing the amount of blood pumped from the heart as your heart is made to work harder. This makes the heart healthier and gives your body a rosy complexion, according to an article published in Prevention Health magazine. -
Increase in energy:
Workouts, in general, make people feel more energetic on a daily basis. Compared to regular training, power workouts increase the rate at which calories are burnt by the body. -
Weight loss:
With power training, your body tends to break down the calories and sugar faster than normal training, and this aids in weight loss.
Strength and power training together helps tone your muscles and make you lose that extra weight. -
Decrease in stress:
Power training helps release more endorphins, which are hormones that help relieve stress and pain. -
May prolong life:
A study done in Brazil with non-athlete participants showed that people with more muscle power tend to live longer. -
Reduces fall risk:
As your body power increases, your reaction time improves, and this helps you to react quickly when you lose your balance. This is beneficial in older people who are more prone to falling.
How Does Genetics Influence Power?
ACE Gene and Power
ACE is a gene that codes for angiotensin I-converting enzyme. It regulates blood pressure, cardiovascular function, and metabolic processes in muscles.
rs4343
rs4343 is an SNP in the ACE gene with two alleles, I and D. I allele, which is the inserted form, is associated with improved endurance, and D allele, which is the deleted form, is found to be associated with higher enhanced performance at sports that require bursts of power.
ACTN3 and Power
ACTN3 is primarily expressed in skeletal muscle. This gene codes for a protein called Alpha-Actinin-3, which is necessary for producing explosive power contractions. These two genes have been extensively studied in link with human physical performance, fitness, and athletic ability.
rs1815739
rs1815739 is an SNP in the ACTN3 gene with two alleles, R and non-functional X. According to a study, the R allele is found in sprint athletes, whereas the X allele results in higher endurance. The R allele is suggested to contribute to power performance.
Other than these two, there is a list of genes that influence power that include ADRB2, AGT, CRP, DMD, WAPAL, among others.
Non-genetic Factors that Influence Power
-
Age
Muscle and skeletal power tend to decrease faster with age. People of all ages can increase their power through training, but the rate at which it is done becomes slower with age. -
Gender
In general, men are known to have more quantity of muscle tissue than women because of testosterone, the male sex hormone. -
Limb and muscle length
People with shorter limbs can lift more because of their advantageous leverage factors (arms and legs). People with longer muscles can develop greater strength and size compared to people with shorter muscles.
Improving Your Power
Power training is strength training done at a faster pace in an explosive amount of time. This will help build muscle and increase energy. Some power exercises are basically strength exercises done at a faster speed.
To have an overall balanced training, power training should be combined with strength training and other types of workouts. Power is an important component of HIIT (High-Intensity Interval Training) workouts.
A few normal exercises that can be done at home without any special equipment to help improve your power are:
- Chair stand
- Bridge
- Tricep dips
- Push-ups
- Jump squats
- Squat thrusters
- Long jumps
These exercises should be done with proper form. The stabilization of your core is of prime importance. The power variations in your workout routine should be gradually increased
Summary
- Power is the ability to exert maximum force in minimum time. Power training is an important part of fitness and sports.
- Including power training in your fitness regime has a number of benefits. It strengthens your bones, muscles, increases energy, helps in weight loss, and gets more blood pumping for a healthier heart.
- Variations in certain genes are found to contribute to your power performance. The D allele of SNP rs4343 found in the ACE gene and the R allele of SNP rs1815739 found in the ACTN3 gene are found to be associated with increased power performance.
- Age, gender, muscle, and limb strength can also influence power.
- Power training can be improved by including various types of workouts. Power is an important component of HIIT workouts.
References
https://www.medicalnewstoday.com/articles/325004
https://www.health.harvard.edu/blog/power-training-provides-special-benefits-for-muscles-and-function-201304226097
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3554644/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879442/
Cholesterol and Its Types
Cholesterol is a waxy, fat-like substance that is present in all the cells of the body. It is used by the body to build cells and make vitamins and other hormones. Cholesterol is, as such, not bad for the body. The problem occurs when excess cholesterol is present in the body. Cholesterol is produced by the liver. It is also found in some foods, like meat and dairy products.
Cholesterol is a combination of fat (lipid) and protein and hence is a lipoprotein. The three types of cholesterol found are HDL (high-density lipoprotein), LDL (low-density lipoprotein), and VLDL (very-low-density lipoprotein). HDL is termed as good cholesterol, whereas LDL and VLDL are termed as bad cholesterol. Excess buildup of LDL and VLDL contributes to the buildup of plaque in the arteries. This results in the blockage of the arteries preventing proper blood flow.
How Does Exercise Impact HDL cholesterol?
One of the main ways to control the levels of bad cholesterol and increase HDL levels is physical activity. Exercise is known to be beneficial for a healthy lifestyle. Regular exercise can prove to be good for your body in several ways. It helps reduce weight and raise the HDL (good cholesterol) levels in your body to a certain extent. Lifestyle changes like dietary changes, stress management, weight loss, and quitting smoking can help maintain cholesterol levels.
Research shows a direct link between exercise and an increase in HDL levels and a subsequent effect on LDL levels. The beneficial effects of aerobic exercise, resistance training, and combined exercise on cholesterol are detailed in a review based on previous investigations done. The impact of different types of exercise, intensity, and exercise recommendations have also been studied and listed.
In a meta-analysis conducted in Tokyo, researchers studied the effect of exercise type, frequency, and intensity on HDL cholesterol levels. The study participants exercised for about 40 minutes three to four times a week, on average. The HDL levels were measured after eight to twenty-seven weeks of exercise. A statistically significant increase in HDL cholesterol level was found across participants, and a drop in cardiac risk was also reported. The major takeaway from this study was that exercise duration has a major effect on the increased HDL levels compared to the frequency or intensity of exercise. According to this study, at least 20 minutes of exercise, three to four times a week would help increase HDL levels.
Another study reported that physically active women have significantly higher levels of HDL cholesterol compared to sedentary women. This study included participants that were free from any cardiovascular diseases.
Yet another study found that regular endurance exercise helps men with belly fat, low HDL cholesterol, and elevated triglyceride levels. The study concluded that regular endurance exercises could increase HDL cholesterol levels.
High-density Lipoprotein and its importance
HDL, referred to as good cholesterol, is responsible for removing other harmful forms of cholesterol from the blood. It carries cholesterol from different parts of the body to the liver, which removes cholesterol from the body.
How Does Genetics Affect The Influence of Exercise on HDL Cholesterol Levels?
The PPARD Gene And The Influence of Exercises on HDL Cholesterol Effects
The PPARD gene encodes a protein called peroxisome proliferator-activated receptor delta. This belongs to a family of proteins that bind to other proteins or molecules termed as ligands. These proteins are called receptors. On binding, the receptor controls the expression of a gene called PPRE. This leads to changes in various factors involved in the metabolism of energy substrates, like lipids and carbohydrates.
The delta form of this protein is known to have a role in the breakdown of fatty acids (like cholesterol), insulin sensitivity, and energy uncoupling.
rs2016520 and HDL Levels On Exercising
rs2016520 is an SNP in the PPARD gene. According to a study done in 2018 with female participants, the C allele is associated with a decrease in cholesterol levels through training and a decrease in triglycerides.
Non-genetic Factors That Affect HDL Cholesterol Levels
Sedentary lifestyle
People who do not exercise regularly are known to have lower HDL levels. Regular physical activity is a major contributor to increasing HDL levels.
Smoking
The chemicals found in cigarettes are known to decrease HDL levels.
Weight
People who are obese or overweight have lower HDL levels. Losing weight can help increase levels of HDL.
Food
Diet can also play a role in influencing HDL levels. Food that contains a lot of trans fat is known to increase LDL levels and decrease HDL levels. These include cakes and fried foods. Substituting these fats in your diet with food containing monounsaturated fats like olives, avocado, and fatty fish can help increase HDL levels.
Effects of Insufficient HDL in the Body
Below 40 mg/dL HDL level is known to increase one’s risk of developing heart disease. In women, the lower limit for being at risk of heart disease is around 50 mg/dL. HDL levels above 60 mg/dL are associated with a lower risk of heart disease.
In most people, high HDL levels are a good sign and reduce the risk of developing cardiovascular issues. It is always advised to maintain recommended levels of cholesterol to maintain a healthy lifestyle.
Improving Your Exercise Routine
As exercise is effective for keeping cholesterol in check, a proper exercise routine should be followed. The amount of time you exercise for is equally important as the type of exercise you do. It is always good to be physically fit to keep your body in check.
-
A good jog or run (if you’re up for it) is known to be a great exercise to keep your cholesterol levels in check. According to a study done in 2013, long-distance runners (more than 10 miles a week) have abetter improvement in cholesterol levels and blood pressure compared to short distance runners.
-
A brisk walk is also effective in increasing HDL levels. The distance covered by walking should be greater than that by jogging or sprinting to get the same amount of benefit. It all depends on the amount of energy you exert while doing the physical activity.
-
Cycling is another exercise that is less stressful on your joints than jogging or running. Cycling is found to reduce the risk of cardiovascular disease. People who cycled to work are less likely to develop high cholesterol compared to people who don’t, as reported by a study.
-
Another beneficial aerobic exercise is swimming. It is found to help more with weight loss, fat reduction, and lowering LDL cholesterol levels as compared to walking.
-
Lifting weights combined with aerobic exercise can help keep your heart healthy.
-
Yoga is also known to reduce cardiovascular disease risk. Regular practice of yoga keeps your cholesterol levels in check.
-
A healthy lifestyle, including at least 30 minutes of proper exercise a few days a week, is very important to keep your cholesterol levels in check and reduce your risk of cardiovascular diseases.
Summary
- Cholesterol is a combination of fat and lipids and is produced by the liver. Excess of bad cholesterol is harmful as it contributes to a higher risk for cardiovascular diseases.
- HDL, also known as good cholesterol, helps in removing the bad cholesterol from the body. Higher levels of HDL are known to be beneficial to the body, especially in reducing the risk of heart disease in healthy individuals.
- Regular physical activity is shown to help increase HDL levels and reduce levels of bad cholesterol in the body.
- Studies show that aerobic exercise, resistance training are effective ways to increase HDL. The duration of physical activity is found to be an important factor in increasing HDL levels compared to the type of activity done.
- A modification of the PPARD gene influences cholesterol levels after physical training. The C allele of SNP rs2016520 has been associated with a decrease in cholesterol levels in the course of training.
- Non-genetic factors like diet, weight, and smoking also affect HDL levels.
- Jogging, swimming, lifting weights, aerobic exercise, yoga, and cycling are some of the physical activities that contribute to increasing levels of HDL and reducing levels of bad cholesterol.
References
https://medlineplus.gov/cholesterollevelswhatyouneedtoknow.html
https://www.healthline.com/health/high-hdl#issues
https://www.medicalnewstoday.com/articles/319275#hdl-is-higher-always-better
https://www.healthline.com/health/high-cholesterol/treating-with-statins/best-exercises#Best-exercises-for-lowering-cholesterol
https://www.webmd.com/cholesterol-management/features/cholesterol-how-much-exercise
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6114845/
The heart capacity is a measure of the amount of blood your heart pumps every minute. It is calculated using the following equation:
Heart Capacity = heart rate x stroke volume
Stroke volume is the amount of blood your heart pumps every time it beats. The capacity of the heart to pump enough blood every minute ensures all organs receive oxygen and essential nutrients.
For a normal individual who is resting, the heart pumps 5-6 liters of blood every minute.
How Does Exercise Affect Heart Capacity?
When exercising, your muscles rapidly use up oxygen. In order to keep up with demand, your heart pumps faster, and hence your heart rate increases. In order to keep up with demand, your heart pumps faster, and hence your heart rate increases. When your heart rate increases, your heart capacity or cardiac output increases.
Importance of Exercise for Heart Capacity
Exercising is considered important for the heart’s health. Here are some of the benefits of exercise for heart capacity.
Stronger Heart Muscles
Just like how exercise strengthens the rest of your body muscles, it strengthens the heart muscle too. A stronger heart pumps blood better.
Your Body Receives More Oxygen
With regular exercise, your body can receive/absorb oxygen from the blood better. This puts less strain on the heart when it pumps blood.
Improves Blood Flow Through Vessels
Studies show that with regular exercise, the blood vessels dilate to allow more blood flow.
Regulates Blood Pressure
Blood pressure is a very critical factor that talks about your heart’s health. By exercising, your blood pressure slowly drops down to normalcy without putting excess pressure on the heart’s pumping capacity.
Reduced Resting Heart Rate (RHR)
An increase in your Resting Heart Rate (RHR) is associated with increased mortality. Exercise helps bring down the resting heart rate. The RHR for athletes can be as low as 40 bpm.
The Influence Of Genetics On Heart Capacity
CREB1 Gene and Heart Capacity
The CREB1 gene encodes the CAMP Responsive Element Binding Protein 1, which plays an important role in several biological pathways. Variations in the gene are proven to cause various diseases, including memory disorders and Huntington’s disease.
The rs2253206 SNP in this gene causes changes in heart rate while exercising. The AA genotype causes heart rate improvements because of exercises. The AG and GG genotypes show no such positive relation.
Non-genetic Influences On Heart Capacity
Just like how exercise changes your heart capacity, other non-genetic factors increase or decrease your heart’s ability to pump blood.
Hormones - Certain hormones affect the contraction of the heart and hence affect stroke volume.
Stress - Norepinephrine is a chemical released in the body when you are stressed. This chemical right away increases heart rate, which in turn increases heart capacity. Epinephrine is another chemical the body produces when the person experiences fear or anger. This also increases the heart rate and pumping capacity.
Changes in body temperature - Increased body temperature can cause increased heart rate and heart capacity
Sex - Women have a higher heart rate than men, and hence their heart pumps blood faster.
Age - The heart rate and capacity to pump blood is the fastest at birth and reduces slowly as people age.
What Happens When Your Heart Capacity Is Higher Than Normal?
It is quite normal for the heart capacity to increase during exercise and other external factors. However, when the heart capacity or cardiac output is consistently high, it can lead to pulmonary edema (fluid accumulation in the lungs). This can be a life-threatening condition.
If exercising causes abnormal increases in heart rate and heart capacity, you may have to slow down the intensity of working out and give the body adequate resting time to stabilize.
What Happens When Your Heart Capacity Is Lower Than Normal?
When the heart capacity is lower than normal, it gets difficult for the other parts of the body to receive oxygen. For maintaining your heart’s pumping capacity, the heartbeat increases to pump more blood with every passing minute.
The adrenaline glands release adrenaline that reaches the heart and pushes it to beat faster. Consistently lowered capacity and higher heart rate can weaken the heart muscles with time.
Recommendations To Improve Heart Capacity With Exercise
Start slow
Exercise definitely helps your heart capacity improve. However, start slow and let the heart get used to all the physical exertion. As your capacity improves, you can start training intensively.
Listen to your heart
Does exercising leave you tired, breathless, or dizzy? Get the core problem checked before you continue to exercise. If you are genetically designed to experience high blood pressure or abnormally high heart rate because of exercise, you could feel worse after a workout session.
Moderation is the key
A healthy individual who is not trained by a professional should consider moderate exercises over high-intensive training.
Improve your recovery heart rate after exercise
Aim to improve your heart rate recovery after exercise. Follow a mix of light, moderate, and intense exercises to get your heartbeat to normalcy quickly.
Summary
- The heart capacity is the amount of blood the heart can pump every minute. Heart capacity is measured as heart rate X stroke volume.
- When you exercise, your heart rate increases, and hence your heart capacity increases too.
- Exercising brings down blood pressure levels, keeps you fit, strengthens your heart muscles, and reduces Resting Heart Rate (RHR)
- Certain variations in the CREB1 gene can significantly improve heart rates because of exercise. Variations in the CHRM2 gene cause increased risks for lowered heart rate recovery after exercise.
- Non-genetic factors like age, sex, stress, and hormones also decide how much blood your heart can pump during and after exercising.
- Moderate exercises give the body time to recover and improve your heart recovery rate.
References
https://wa.kaiserpermanente.org/healthAndWellness?item
https://medicalxpress.com/news/2018-09-genes-heart.html
https://www.health.harvard.edu/heart-health/what-your-heart-rate-is-telling-you
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6529381/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2575587/
https://www.medpagetoday.com/blogs/skeptical-cardiologist/83528
https://www.uofmhealth.org/health-library/tx4080abc
https://www.theonlinelearningcenter.com/assets/carter/46/course_01/module_04/mod_04.pdf
Aerobic capacity (AC) is the maximum amount of oxygen consumed while performing intense activities that involve large muscle groups.
It is also a measure of how effectively the heart and the lungs get oxygen to the muscles. Hence, improving your aerobic capacity can directly result in more efficient use of oxygen by the body.
The other term which is used to describe aerobic capacity is VO2 max.
However, the VO2 max also takes into consideration the individual's body weight.
Importance of Aerobic Capacity
Improves Cardiovascular Health
Improving aerobic capacity strengthens your heart and helps it pump blood throughout the body more efficiently. In fact, aerobic exercises are recommended by the American Heart Association for those who are at risk for heart diseases.
Aids Better Sleep
A study reported that aerobic exercises improve sleep quality in adults with insomnia.
Helps Ward Off Viral Diseases
Improving your aerobic capacity can boost your immune system and gear it up to fight viral infections like cold and flu.
Increases Your Stamina
Though aerobic exercising can be tiring initially, building up your aerobic capacity also improves heart and lung capacity. All these factors can help build up your stamina.
Lowers Blood Pressure
Aerobic exercises help lower blood pressure. A meta-analytic study reported the effects of aerobic exercise training in lowering both systolic and diastolic blood pressure.
Boosts Your Mood
Aerobic exercising helps alleviate the symptoms of mental conditions like depression and anxiety. It also promotes relaxation of the mind.
Reduces Chronic Pain
Low impact cardio activities can help with chronic back pain. They also may help improve endurance and get back some muscle function.
Helps with a Longer Life
Studies suggest that people who engage in regular aerobic exercise live longer than those who don't. They also have a lower risk of dying of conditions like heart disease and certain cancers.
How does Genetics Influence Aerobic Capacity?
A study conducted by a consortium of five universities in the United States and Canada revealed astonishing variation in the aerobic capacity amongst 481 participants. The study subjected its participants to identical stationary-bicycle training regimens with three workouts per week of increasing intensity under strict control in the lab.
The results
- 15% of participants showed little or no aerobic capacity gain
- Up to 15% of the participants showed a 50% increase in the amount of oxygen their bodies could use
VEGF-A and Aerobic Capacity
VEGF-A is a gene that encodes Vascular endothelial growth factor A. VEGF-A has important roles in mammalian vascular development and diseases involving abnormal growth of blood vessels. Variations in the VEGF-A gene influence heart structure, size, and function. These have an impact on the stroke volume, which is an important determinant of aerobic performance.
rs2010963 and Aerobic Capacity
rs2010963, also known as G-634C, is an SNP in the VEGF gene. The C allele has been associated with better aerobic capacity. According to a study, GC and CC genotypes were found to have higher values of aerobic performance.
Other genes like ADRB2, CAMK1D, CLSTN2, CPQ, GABPB1, NFIA-AS2, NRF1, PPARA, PPARGC1A, and PPP3CA also influence the aerobic capacity of an individual.
Non-genetic Factors that Influence Aerobic Capacity
Sex: Men have higher VO2 max than women. This is because women have smaller hearts, lower hemoglobin, and more fat, all of which influence oxygen delivery to muscles.
Age: VO2 max decreases with age. After 25, it reduces at the rate of about 1% per year.
Body size: Larger body size and greater musculature is associated with higher VO2 max. This is also partly why men have a higher VO2 max.
Fitness levels: A fit person may has a higher aerobic capacity and VO2 max than a sedentary person of the same age and sex.
Improving Aerobic Capacity
Genetics is only 50% of the fitness story. The rest wires down to other factors like your lifestyle, what you eat, and how hard you train.
Augmenting your aerobic capacity can result in better blood and oxygen flow to muscles.
This promotes faster recovery between sets and improves your flexibility.
Aerobic exercises include walking, running, cycling, swimming, and almost every other cardio workout.
When aerobic exercises are performed, your heart is trained to deliver more oxygen in a said span of time. At the same time, your muscles are trained to utilize the oxygen delivered more efficiently.
To improve your aerobic capacity, it is important to understand how your body builds endurance.
It depends on the following three things:
1. Heart rate (number of beats per minute)
2. Stroke volume (amount of blood pumped out with each beat)
3. Cardiac contractility (a measure of the force with which the heart muscles contract)
When you train to increase all the above-mentioned variables, naturally, the amount of blood and oxygen reaching your muscles increase.
This, in turn, has a positive effect on your overall athletic performance.
HIIT workout (High-intensity interval training): Studies show that HIIT workouts increase mitochondrial density. This directly results in an increased amount of oxidative enzyme. As a result, the functioning of your skeletal muscles is enhanced.
You can start with a simple 10-minute workout consisting of three sets.
Gradually you can increase the duration, and at the same time, try to fit in more sets.
LISS training (Low-intensity steady-state training): LISS training is the less popular cousin of HIIT. Though it is not as effective as HIIT in burning calories, it is a slow, steady, and lower-stress way to improve AC.
List of aerobic exercises
Aerobic training usually targets large muscle groups of your body that boost your heart rate for longer periods of time.
Some of the commonly recommended aerobic exercises include
Walking and running: Other than helping you lose weight, walking and running at moderate paces also help people with joint problems.
If you do not have access to outdoor space, treadmills can also work.
Swimming: Water aerobics in general, are easy on your joints due to the buoyancy offered by the water
Cycling: Cycling is an amazing leg workout and exerts lesser stress on joints compared to walking or running
Some of the aerobic exercises that you can do at home include:
- Skipping
- Burpees
- Squats
- Jumping jacks
- Running in place
Summary
- Aerobic activities increase the oxygen availability for muscles by increasing the physical capacity of the heart, lungs, and blood vessels.
- Genetics partly influences the aerobic capacity of an individual. The VEGF-A gene plays an important role in vascular development. According to a study, the C allele of SNP rs2010963 in the VEGF-A gene is associated with higher aerobic capacity.
- Improving your aerobic fitness can help improve your cardiovascular health, lower blood pressure, aid better sleep, and reduce chronic pain.
- HIIT and LISS workouts can help improve aerobic fitness. Some at-home exercises like skipping, squats, and jumping jacks also increase your aerobic capacity.
Reference
https://www.sciencedirect.com/science/article/abs/pii/S1389945710002868
https://www.tandfonline.com/doi/full/10.3109/08037051.2013.778003
https://www.ncbi.nlm.nih.gov/pubmed/21633119
https://www.pbrc.edu/heritage/
https://www.researchgate.net/publication/226018635_Polymorphism_of_the_vascular_endothelial_growth_factor_gene_VEGF_and_aerobic_performance_in_athletes
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4968829/
Despite knowing the numerous benefits of exercising, it’s just too hard to get up and get moving on some days. Not for everyone though. Some people seem to have a lot of energy all day around. Why does that happen? Why are some people motivated to work out while others need that extra push?
It may take around eight weeks for a beginner to become a regular exerciser according to behavioral research. However, studies show that 50% of people starting an exercise program will drop out within the first six months.
Exercise initiation depends on three factors:
- Self-perception
- Social support
- Positive feedback
After initiation, other factors motivate the person to continue exercising:
- Biological characters (the sex of an individual, being overweight)
- Social factors (the level of fitness and physical activity of people around you)
- Psychological factors (self-efficacy, self-confidence)
- Behavioral attributes (diet, alcohol consumption, smoking habits)
- Physical environment (exercise facilities, equipment)
- Genetic factors
Types of Exercise Motivation
There are two types of motivation, namely, extrinsic and intrinsic.
Extrinsic Motivation
Some examples of extrinsic motivation or external motivators are:
- Getting flat abs
- Wanting to fit into old clothes
- Improving appearance
Intrinsic motivation
Intrinsic motivation is something that comes from within. Some internal motivators are:
- Runner’s high
- Stress relief
- ‘Feel good’ factor
How Do Genes Influence Exercise Motivation?
BDNF Gene and Exercise Motivation
The Brain-Derived Neurotrophic Factor (BDNF) gene encodes the protein by the same name. This protein is found in the brain and spinal cord. It is especially found in the regions of the brain that control eating, drinking, and body weight. Hence, the protein influences all of these functions.
rs6265 in BDNF Gene and Exercise Motivation
rs6252 is an SNP in the BDNF gene, which has been associated with exercise motivation. The G allele of this SNP has been associated with a lower motivation to exercise. It is also linked to a higher risk for weight gain.
Other genes like C18orf2, DNAPTP6, and PAPSS2 also influence exercise motivation.
Non-genetic Factors Which Affect Exercise Motivation
Sex: Men are more likely to engage in workouts based on competitiveness, while women are more interested in workouts that alleviate stress and improve physical appearance.
Psychological: Low levels of self-esteem affects women’s exercise participation and adherence, as they tend to gain less satisfaction from exercise engagement.
Sedentary lifestyle: A lifestyle that involves a lot of sitting makes it all the more difficult to get up and get the body moving.
Exercise injuries: Working out with the wrong form or improper technique can lead to injuries. This may discourage people from working out again.
Recommendations to stay motivated
Set up achievable goals: It is important to set realistic goals that are best suited for you. If you are new to exercising, you may want to lighten your goals. For beginners, it is advisable to start with 20-30 minutes 2-3 times a week.
Remember to reward yourself: Sometimes, vague goals like weight loss or better health may not feel rewarding enough as they may take a while to achieve. By treating yourself to a delicious treat after a good workout, you create a kind of reward loop in your brain. In fact, you can trick your brain into growing fond of this link between exercise and reward. This may increase your willingness to commit to the workout.
Find a routine you like: It is important to workout because you ‘want to’ and not because you ‘have to.’ If you don’t love any exercise in particular, walking may be a good start.
Get some reliable support: A good workout buddy can go a long way. Even on the days you don’t really feel like it, having a support system in place can help you kick the lull.
Don’t be too hard on yourself: It is completely normal to miss out on a day or two of workouts. In fact, such ‘rest days’ are recommended for the sore muscles to heal.
Summary
- While a lot of people enthusiastically initiate exercising with a future goal in mind, only 50% stay on the routine after six months. Many biological, social, and behavioral factors influence the motivation to exercise.
- Certain genes have been implicated in exercise motivation. BDNF is one such gene that encodes a protein found in the appetite and weight control regions of the brain. rs6525 is an SNP in the BDNF gene. The G allele of this SNP has been associated with a lower motivation to exercise.
- Other factors like lifestyle and psychology also come in to play in exercise motivation. For example, a sedentary lifestyle and low self-esteem are associated with a lower motivation to exercise.
- Setting realistic fitness goals and rewarding yourself after a good workout are effective ways to keep yourself motivated. It is also recommended to find a workout buddy who can act as a support system.
Reference
https://www.researchgate.net/publication/254301548_Effect_of_Goal_Setting_on_Motivation_and_Adherence_in_a_Six-Week_Exercise_Program
https://pubmed.ncbi.nlm.nih.gov/24805993/
Endurance refers to your body’s physical capability to exert itself for long periods of time. Individuals with good endurance levels can sustain exercise for an extended period.
Endurance has two components:
1. Cardiovascular endurance: The level at which your heart and lungs work together to deliver oxygen to the body while exercising
2. Muscular endurance: Ability of your muscles to perform contraction against a resistive force for extended periods
Importance of Endurance Training
Improves Bone Density
Exercise, in general, is known to improve bone density and overall bone health. According to a study, there was an increase in the lumbar bone density in people who underwent weight training, compared to the control group.
Enhanced Immune System
Endurance training helps increase the white blood cells, which are the quarterback of the immune system.
Improved Metabolism
Endurance and resistance training help build muscle mass. As your muscle mass builds up, your body burns more calories.
Better Mental Health
Endurance training seems to have an effect on mental health by regulating the release of endorphins. It is also associated with chemical signals that are involved in pain sensations and inflammation. Endurance training may positively impact depression and mood swings - the reasons behind it have not been clearly identified.
Impacts Weight Control
Glucose in the blood is used for energy production when performing exercises that increase the heart rate for a short duration. Sustaining exercise for a longer duration keeps your heart rate high for a significant amount of time. This results in tapping the body fat for energy, thus helping you lose weight.
How Does Genetics Influence Endurance?
A 2016 study identified 93 genetic markers associated with endurance. Some variants allow your muscle to contract and relax repetitively for a longer duration, while the others may hinder this process.
These variants also influence other endurance-related aspects like:
The type of fuel used by the cells for energy production
The percentage distribution of muscle fibers (slow twitch and fast twitch)
The adaptability of the blood vessels to carry more oxygen.
ACE Gene and Endurance
ACE gene encodes angiotensin I converting enzyme. This enzyme plays a role in balancing electrolytes and regulating blood pressure in the body. The enzyme also influences capillary supply lines (blood flowing through narrow vessels) and aerobic (oxygen-dependent) metabolism in skeletal muscle.
rs4343 in ACE Gene and Endurance
rs4343 is an SNP in the ACE gene. It causes a G to A transition. The G allele is associated with deletion variation (one or more letters are removed from the sequence - D), and the A allele is associated with insertion variation (one or more letters are added to the sequence - I). Studies have found the A allele (ACE/I) to be commonly present among endurant athletes.
ACTN3 Gene and Endurance
ACTN3 gene encodes the Actinin Alpha 3 protein and is primarily expressed in the skeletal muscles - type 2 muscle fibers. Fast-twitch/type-2 muscle fibers are associated with the ‘sprinter’ variant. The slow-twitch fibers, on the other hand, are associated with the ‘endurant’ variant.
rs1815739 in ACTN3 Gene and Endurance
rs1815739 is an SNP in the ACTN3 gene. It causes a T to C transition. C is associated with fast-twitch fibers and promotes sprinting-based activities. People with the C allele may be better at sprinting than endurance-based activities.
ADRB1, COL5A1, GABPB1, HIF1A, and 47 other genes are also associated with endurance.
How Can You Improve Your Endurance?
The following tips can help in building endurance:
Push Through Some Yasso 800s
The concept behind Yasso 800s is pretty simple. Take your goal marathon time and then run 800 meters in that time; one small change - use minutes and seconds in place of hours and minutes. For example, if you’re trying to run a 4:15 marathon, your Yasso 800m goal time is 4 minutes and 15 seconds.
Sink Into Some Tunes
Listening to good music improves your cardiac efficiency by lowering your heart rate. This enables you to perform the task at hand for a much longer duration with maximum efficiency.
Get Caffeinated
Caffeine shot gives a boost to the energy, which can help you complete rigorous tasks. However, it is important to be wary of how much caffeine your body can tolerate.
Exercises to boost your endurance
- Jogging/Running
- Swimming
- Cycling
- Weight lifting
- Crunches-squats-lunges circuit
- Yoga/pilates
Summary
- Endurance allows your body to sustain exercises for a longer duration. There are two components of endurance, namely, cardiovascular and muscular endurance.
- Endurance training offers many health benefits, including improving bone density, enhancing the immune system, and regulating body weight.
- Genes that influence endurance play a role in the percentage of different types of muscle fibers, the ability of blood vessels to carry blood, and how the body uses fuel for energy production.
- ACTN3 is a gene that is associated with muscle fiber distribution. The presence of the T allele indicates a higher number of slow-twitch fibers, which are important for endurance. People with TT type tend to be better at endurance-based activities.
- Listening to music and caffeine consumption can improve an individual’s endurance. Exercises that boost endurance include jogging, swimming, cycling, and yoga.
Reference
https://pubmed.ncbi.nlm.nih.gov/1642145/
https://pubmed.ncbi.nlm.nih.gov/27287076/
https://medlineplus.gov/genetics/gene/ace/
https://pubmed.ncbi.nlm.nih.gov/9737775/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741991/
https://pubmed.ncbi.nlm.nih.gov/26824906/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4948383/
https://www.healthline.com/nutrition/caffeine-tolerance