Physical inactivity has become a pandemic but there is an obvious solution: the need to exercise. Scientific research, however, suggests that there is no definite guarantee that your body will get a boost from a training program. What’s the trouble?

By Jurgen van Teeffelen

When Claude Bouchard started his research on the health effects of exercise at Laval University in Quebec City in the 1980s, he quickly noticed that some of his subjects responded well to the training but that others did not. Previous researchers had suggested this as well, but they were not absolutely sure that all participants had properly followed the prescribed training program. However, this was not the case in the Canadian study: all subjects followed a tailored exercise protocol and Bouchard personally monitored that everybody adhered to it. Yet, after he had carefully analyzed the collected data, Bouchard could not fully understand one thing: why did some people show no benefit from more exercise, or even worse, deteriorated?