A recent article in the NY Times (see excerpt below) argues that both too much and too little exercise could be bad for you. The difficult part is to get the balance right.
That’s just what Smart Marathon Training is all about: varying the modes and stresses of training to get the most from your workouts while minimizing the risk of overuse injury and strain. Train smart!
Personal Best: Workouts Have Their Limits, Recognized or Not
By GINA KOLATA, January 16, 2012
While public health officials bemoan the tendency of most people to do little exercise, if any, physiologists are fretting over the opposite trend: an increasing focus on extreme exercise among some recreational athletes. Weight lifting with no rest between sets and with no days off. Endurance training with no easy days or days off. Competitions that encourage excess.
It’s not so easy to strike the right balance between exertion and rest, researchers say. Do too little, and the results may be disappointing.
Experienced athletes know that the only way to improve is to push yourself. You should feel tired, said John Raglin, a sports psychologist at Indiana University. But if you do too much with too little rest, your performance gets worse, not better.
Muscles need to recover after they are stressed with heavy weights, Dr. Kraemer noted. Researchers have long known that the way to build strength is what they call periodization: Rest days and easier days and weeks are interspersed with periods when the weights are increased.
In endurance sports, muscles experience a different kind of stress, said Dr. Bengt Saltin, director of the Copenhagen Muscle Research Center at the University of Copenhagen. But the problem with intense exertion day after day is very similar.
Intense endurance exercise depletes muscles of their energy supply, glycogen. Muscles store enough glycogen only for an hour and a half to two hours of activity, Dr. Saltin said.
It takes a day for trained endurance athletes to replenish glycogen. Athletes with less training have less of the enzyme that restores glycogen — glycogen synthetase. It can take up to two days for them to restore this muscle fuel.
In addition, connective tissue in muscles can be damaged and needs time to recover. In a study of runners in an annual local race that is a bit longer than two marathons, Dr. Saltin and his colleagues found that the athletes’ muscles lost their elasticity as their connective tissues weakened.
So how to avoid a self-defeating training program? There are no hard and fast rules, because individual athletes vary so much. A training program that one person thrives on will break another, equally talented athlete.
Dr. Raglin said even the experts, researchers like himself who study overtraining, had trouble defining the symptoms. Psychological changes are the most consistent signs of a problem, he said. In the early stages of overtraining, athletes constantly feel tired; by the end stage, they may be nagged by depression.
Recreational athletes must be attuned to their fatigue, Dr. Raglin said. And that does not mean that difficult regimens are out of the question, Dr. Raglin said.