Can your genes explain the difference in training results?



Staying physically active is important for maintaining health, reducing chronic disease, and preventing premature death. In accordance with the 2018 Physical Activity Guidelines for Americans, a combination of moderate-intensity and vigorous-intensity aerobic exercise along with muscle-building activity involving major muscle groups is recommended.

The advice for adults is to do 150-300 minutes of moderate-intensity aerobic activity, 75-150 minutes of vigorous-intensity aerobic activity, or an equivalent mixture. This activity can be spread throughout the week and should include strength training at least 2 days for the weakest.

The three important factors in determining health-related fitness are cardiovascular fitness, muscle strength, and anaerobic power.

Cardiovascular fitness measures how efficiently the respiratory and circulatory systems deliver oxygen to skeletal muscles for energy production during physical activity.

The maximal oxygen uptake (V02) test is one way to determine breathing capacity. The VO2 max test measures the ability to consume oxygen during high intensity activity, such as running on a treadmill.

A higher VO2 max indicates an improved ability to deliver and use oxygen and to maintain aerobic activity and increased intensity for a long time. Poor cardiorespiratory capacity is an indicator of cardiovascular disease and death from all causes in adults.

Muscle strength is the body’s ability to exert maximum force against external resistance to perform a task and maintain mobility.

Aerobic activity involves breaking down glucose into energy without using oxygen. It measures the body’s ability to move with the greatest intensity over a short period of time.

Increasing cardiorespiratory fitness, muscle strength, and anaerobic power can improve a person’s overall fitness level. But the response to physical training varies from individual to individual. Genetics can play a role in how your body responds to the physical activity you do.

Role of genetics in the impact of physical activity on your body

According to the 22nd Annual Congress of the European College and Sports Sciences, the environment is a major factor for trainability and nowadays we know that around 25 to 40 percent of the variability in the phenotype comes from the genes. and the remaining 60 to 75 percent comes from environmental factors.

Specific genes called candidate genes can predict successful responses to targeted types of physical training. These genes can affect energy pathways, metabolism, storage, and cell growth in the body.

These findings led scientists at the Cambridge Center for Sport and Exercise Sciences at Anglia Ruskin University, UK, to conduct a meta-analysis to identify the specific version or alleles of candidate genes linked to the response to the exercise in untrained participants. The team analyzed the strength, anaerobic power and cardiopulmonary shape of these candidates.

Individuals inherit one allele of each gene from each parent. The individual is homozygous for the gene if the two alleles are identical and heterozygous if the two alleles are different.

The study assessed whether the identified genes and alleles contributed to the difference in response to exercise training among the participants. The results of 24 studies involving 3,012 participants were analyzed, of which 1,512 participants were men and 1,239 were women. The gender of the remaining 261 participants was not specified.

The average of these participants was 28 years old. 89 groups were formed, 43 aerobic, 29 in strength and 17 in power. Scientists identified 13 candidate genes and alleles, nine, six and four of which were associated with cardiorespiratory fitness, muscle strength and anaerobic power, respectively.

Variable effects

Participants in the cardiorespiratory fitness studies received aerobic training for 36 minutes 3 days a week for 12 weeks. The intensity specified was 77% of maximum heart rate or 74% of VO2 max.

The researchers attributed 44 percent of the difference in aerobic training response to genetic influences.

Strength training involved 174 repetitions per session at an intensity of 75 percent of the maximum of one repetition. The sessions took place three days a week for 10 weeks. Genes accounted for 72 percent of the differences seen in the bodybuilding group.

The anaerobic power group performed an average of 4 to 12 cycle periods of a specified intensity – 90% to 110% VO2 max or a load of 0.075 per pound of body weight – 3 days per week for 5 weeks. In potency, group genes have less influence, with only 10 percent of the variability in response being due to genetic influence.



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