Excessive exercise, known as over-training, negatively affects your physical and emotional well-being. In fact, rigorous training programs can hinder athletic performance, increase your risk of injury during exercise and suppress your immune system. Exercise becomes excessive when the intensity, duration or frequency of your workouts interfere with adequate rest and recovery between workouts. Your fitness level dictates how much exercise is too much.
Over-training influences hormone secretion. Endurance athletes, who often perform hours of cardio each day, can experience increased secretion of cortisol -- a hormone associated with stress and weight gain. Additionally, over-training can suppress your appetite by increasing the secretion of two hormones known as epinephrine and norepinephrine. Inadequate caloric intake during difficult training programs can reduce your recovery rate and intensify over-training symptoms.
Immune System Changes
Too much exercise can suppress your immune system. As your body struggles with fatigue and inadequate muscle recovery, energy reserved for proper immune-system function redirects to repair overworked muscles and bones. Reoccurring illness during a workout program indicates a lack of rest and possible over-training. Additionally, training while sick can lengthen your recovery time and hinder your training to a greater extent than taking a few days off from exercise.
Heart Rate Changes
An elevated resting heart rate indicates over-training. For example, sustaining a resting heart rate of 80 beats per minute when your usual resting heart rate equals 65 beats per minute represents an elevated resting heart rate. In addition, exercising too much can increase the time it takes for your heart rate to return to a resting rate after a bout of exercise. Therefore, you should record your resting heart rate throughout your program and take notice if your resting heart rate increases over time.
Your musculoskeletal system comprises muscle and bone. Muscles and bones experience microscopic damage during exercise and require 24 to 48 hours of rest between workouts for adequate recovery. Frequently forgoing adequate rest periods reduces your strength and causes previously easy exercises to become difficult. Attempting exercise in a weakened state can lead to sprains or muscle tears.
Your likelihood of developing over-training symptoms depends on your exercise program and fitness level. Elite athletes who follow proper rest protocols can perform two workouts per day without negative results. On the other hand, an exercise beginner may show signs of burnout after training once a day for an entire month. You should begin a workout program with one or two weekly sessions and increase frequency as you become accustomed to regular exercise. Consult a doctor if you feel you are experiencing symptoms of over-training.
- “ACE Personal Trainer Manual”; American Council on Exercise; 2003
- Ask Dr. Kravitz; Overtraining Undermining Success; Paige Kinucan and Len Kravitz
- American Council on Exercise: Too Much of a Good Thing