Several research reports state that our genes play an important role in how each of us responds to different types of exercise. The first major study that showed variation in training response was published in 1980. In this study, 720 individuals participated in a training program that lasted five months, and the researchers measured the maximal oxygen uptake (the best measure of fitness) before and after the exercise period. Surprisingly, they saw a huge difference in changes of oxygen uptake. A few actually decreased while others increased tremendously.
Their baseline oxygen uptake (that is before they started the exercise program) did not seem to make a difference to the degree of improvement in oxygen uptake. The researchers concluded that about 10 percent of the population had little or no improvement in oxygen uptake after exercise. Subsequent studies have shown that approximately 50 percent of the variation in training response is due to inheritance.
One of the genes that have been linked to the exercise response is called ACE. This gene exists in three variants ACE II, ACE DD and ACE ID. Studies have shown that people with gene variant ACE II, which is about 24 percent of the population, respond better to endurance exercise in the sense that they increase oxygen uptake more than those with the other gene variants. Several studies have shown that people with gene variant ACE II is overrepresented in sports that require great endurance. You can imagine a future dilemma where coach analyzing the ACE variant in junior athletes to help choose which junior competitors that it is worth to invest substantial resources on.
When it comes to strength training, it is however shown that people who have ACE DD gene variant respond better in terms of increased muscle growth, and these are often over-represented in sports that require strength.
We have in recent years become aware of several other genes that are involved in determining response to exercise. In theory, this creates a potential to design an exercise program that is tailored to your own genetic material (DNA). There are already companies that claim they can optimize your training based on a simple genetic test. These tests claim they can show whether you are made for explosive forms of exercise, such as sprinting and weightlifting, or if you are more likely to be good at endurance training such as road cycling and mountain climbing. The tests also claims to be able to say something about your genetic predisposition for exercise-related injuries and how long your body takes to recover after exercise. Based on analysis of dozens of genes, they provide advice on how you should add up your training, how often you should exercise and what you should do to prevent exercise-related injuries.
As the commercial tests today, scientists are generally suspicious. The research still has a long way to go to be able to say something about the interaction between genetic factors and environmental influences. Personally, I would only recommend the commercial tests for those that are particularly interested, and at least advise people to not take the answers to seriously.
Anja Bye, forsker ved CERG
Bouchard C et al, Med Sci Sports Exerc, 2001
Montgomery H et al, Nature, 2000
Ahmetov & Rogozhkin , Plos1, 2009