Returning to sports or exercise after a period of two months or more can be hazardous to one’s health unless properly prepared. The main reason for this is that the human body adapts fairly quickly to “rest”. Many people have the mistaken belief that their body will maintain it’s current state of fitness despite being inactive. Unless the muscles, bones, cardio-vascular system, etc, are being used on a daily basis, they become weaker. Studies show that total inactivity leads to a 10-20% loss of muscle strength every week. That’s about 1-3% loss of strength for every day that you are completely inactive (example: bed rest).

Loss of bone density is especially troubling since it is difficult for the body (over 30 years old) to regain bone density. Twelve weeks of bed rest can decrease bone density up to 50%. The body increases the loss (resorption) of bone mass at a faster rate when there is a lack of weight bearing and muscle activity. It takes years to recover from significant bone loss.

The effects on the cardio-vascular system are just as significant. Lung capacity (measured as VO2 max) decreases about 1% each day, blood volume decreases and resting heart rate increases.

Exercise will help restore bone loss, muscle strength and improve cardio-vascular function—but at different rates. Muscle strength usually increases at a faster rate than cardio-vascular capacity, and bone density improves very slowly. Resuming exercise after a prolonged period of rest frequently leads to injuries, because the various tissues are not properly prepared. That’s the tricky part of starting an exercise program—how much exercise is too much or not enough? Next month I will discuss the proper way to prepare the body for return to exercise/sports.

Visit our Fitness Training page for information about what COAST Physical Therapy Services has to offer you.