Continuing from the last post….
Next, the scientists examined the animals’ hearts. Normally the left ventricle of the heart in animals and people becomes larger and thus able to contract more forcefully after endurance training. The high-responding rats showed these structural changes in their left ventricles, evidence that they were developing athletes’ hearts. The other rats showed almost no physiological adaptations; it looked like they had not exercised at all.
Ulrik Wisloff, a professor at the Norwegian University of Science and Technology explained that this is likely why the animals lost fitness training. If hearts don’t adapt to the demands of exercise, workouts will not strengthen their bodies.
While looking at the gene expression in the animals’ heart cells, scientists found over 360 genes operating differently in the two different groups. These genes direct processes that should increase the size of the heart but were not working as effectively in the animals that were bred to be resistant to exercise. Humans have the same genes in our heart cells. It is impossible to know if our genes respond exactly the same as the genes of rats but it’s possible that they may. However, the interplay of genes and exercise is extremely complex. We are still only in the early stages of understanding effects of environment, heredity, nutrition and even psychology on rates of exercise.
We should monitor our body’s response to exercise. If after months of training and someone is still not able to run any farther than he or she could before, it is time to change the workout. It is likely that the genes that control the body’s response to that activity are different than those involved in responses to aerobic exercise.