We are all aware of how exercise helps our body to become better and makes us fitter. But studies have shown that the reverse is also true.
Following the popular saying that too much of a good thing can be bad, it has been revealed through many studies that too much exercise actually harms the body, particularly the immune system. This can come as a surprise to many of us, but the evidence is there.
Intense vs. Moderate Exercise
Several studies have shown that there has been a direct negative effect on the immune system of people who performed strenuous amounts of exercise without a proper amount of rest in between. Various published papers throughout the years have shown evidence of this fact. Hence, these findings cannot and shouldn’t be taken lightly.
A study conducted in Australia, the results of which were published in 2007, brings light to the suggestion that elite trained athletes, i.e. the ones who perform and exercise harder than moderately exercising people are more susceptible to upper respiratory tract infections or URTI (generally known as the common cold) than people who exercise in small amounts or recreationally.
The study was conducted among a number of elite athletes or people who maintain a hard routine of exercise and people who perform little to moderate amount of exercise. The end results were found to point to the direction that there is a relatively positive chance that high amount of exercise can link to having a bad immune system and get acute URTI symptoms.
Another study was conducted by the Loughborough University in the United Kingdom, the purpose of which was to provide a summary of how exercising affects the immune system. In the paper published after the study was conducted, it was concluded that exercising too much can, in fact, cause a temporary depression of the immune system. This effect of depression of the immune system is noticeable at its peak if the hour of exercise is prolonged more than 1.5 hours and the intensity is too high.
Relation between URTI and Exercise Amount
In most of these studies, there appeared a common phenomenon in the relationship between the amount of exercise and the state of the immune system. It usually is depicted as a J-shaped curve. This J-shaped curve shows the relationship between amount and intensity of exercise and the occurrence or prominence of URTI incidence in the people. Those who had lower levels of URTI illness witnessed in them were usually the recreational athletes and people who maintained a moderate amount of exercise, while the substantially higher rates of URTI occurred among the elite athletes.
The following image of the J-curve is taken from a study conducted and published in 1994, and it depicts the relationship between Risk of URTI and Amount and Intensity of Exercise as follows:
As you can see, it depicts that the way to keep the immune system from any kind of dangerous levels of harm is by pursuing a moderate exercising lifestyle. Whereas, it can be seen that sedentary amount and intensity of exercise, as in those who do too little exercise of lower intensity also possess a threat to their body’s immune system. Likewise, a workout of high intensity and consisting of a longer period of time can be equally, if not more, harmful to the immune system and the body in general.
Some may argue that this being a graph from a study performed way back in time might not be fully correct, given the fact that recent studies have emerged. But despite slight differences, all studies related to this topic the relationship between of exercise and harm to immune system mostly provides the same conclusion as has been drawn in this article. If all their finding were to be taken and recreated as a graph or a pictorial edition, no doubt the end result would look somewhat similar to the one shown above.
Moderation is the key. Exercise too little, and you have the potential danger of making your body unfit, as well as being known as a couch potato. Exercise too much, on the other hand, and you really do have the potential danger of harming your immune system and in turn, your body.
So learn to recognize your body’s signals and gut intuitions. Know when your body can’t take it anymore and give it, and yourself, some well-deserved rest.