Excessive exercise, known as overtraining, 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.
Overtraining occurs when you do too much exercise without adequate rest and recovery between workouts. Over working out can adversely affect all of the body's systems, including hormonal and immune systems, heart rate and the musculoskeletal system.
Hormonal Changes and Appetite Suppression
Overworking the body 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, overtraining 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 overtraining symptoms.
Immune System Changes
Too much exercise can weaken 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.
Recurring illness during a workout program indicates a lack of rest and possible overtraining. 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 can indicate overtraining. 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.
Read more: How Does Exercise Affect Heart Rate?
Musculoskeletal Changes and Rhabdomyolysis
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.
An extreme form muscle damage is known as rhabdomyolysis, or "rhabdo" for short. It occurs when muscle breakdown becomes so severe that the muscle proteins enter the bloodstream. These breakdown products circulate to the kidneys, which must filter them from the blood. However, the proteins themselves break down into substances that damage kidney cells.
As these muscle products filter through the kidneys, the urine turns dark. If left untreated, kidney failure and other serious complications can occur. Rhabdomyolysis can prevented by hydrating adequately and observing rest periods to allow the muscles to recover between workouts. If you suspect you have rhabdomyolysis, you should seek medical care immediately.
How to Prevent Overtraining
Your likelihood of developing overtraining 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 overtraining.
Read more: Cures for Overtraining