What is Exercise Intolerance?

Medically Reviewed by Ross Brakeville, DPT on September 11, 2023
3 min read

Exercise intolerance is the reduced ability of the body to perform strenuous activities. It happens when your body's responses to exercise don't achieve age and gender-appropriate levels. 

It's often associated with heart disease because the heart fails to pump blood properly when exercising but can result from a variety of conditions. You may also experience the condition if you have mitochondrial disease and metabolic disorders.

Exercise intolerance may cause anxiety, especially if you care about your health and are working to improve it. Here are a few other issues it can cause.

Chest pain and discomfort. Exercise intolerance may cause you to have chest pain or discomfort in your left arm, back, and neck. This can arise from exercises such as bench presses and lifting weights.

Unusual and severe shortness of breath. This happens due to insufficient oxygen passing into your lungs.

Excessive sweating. When your body becomes intolerant to exercise, even the slightest form of movement will cause excessive sweating. This is because your body also develops heat intolerance. Excessive sweating could also be a symptom of another underlying condition.

Discoloration of the skin. You may notice changes in your skin color during or after exercise. It may change to purple, bluish, or even a darker shade than usual. The bluish discoloration is often due to low levels of oxyhemoglobin.

Leg cramps and muscle pain. Leg cramps are common and can happen at any time. Under normal circumstances, they last for a short while. You may experience leg cramps during exercise, especially as you advance in age. Cramps are quite uncomfortable and may last from a few seconds to 10 minutes.

Severe fatigue. Your body may lack energy and give you a feeling of exhaustion upon the slightest movement. Working out after you have reached a point of exhaustion may lead to dizziness and shortness of breath. This is a sign of oxygen deficiency in your body.

Exercise intolerance is experienced when you have breathing difficulties after a short period of exercise. When oxygen fails to get circulated in your body, you tire easily and can no longer tolerate movement. If you are unfit and unhealthy, you can have signs of exercise intolerance.

Exercise intolerance can be triggered by muscles that involve the breaking down of glucose into energy, failing to perform as they should.

Exercise intolerance can also develop when the airways (tubes that carry air in and out of your lungs) of your lungs become narrower than usual. This blocks the flow of air in and out of your lungs, causing you to tire quickly.

Muscle fiber failure. Muscle fibers in your body may fail to function correctly due to an underlying defect in the cells that convert food into energy. Your body relies on hundreds of these energy-conversion cells. If there is poor coordination of the same, you will be less energetic.

Injuries. Injuries or disorders of your muscles, nerves, tendons, joints, cartilage, and spinal discs may also lead to exercise intolerance.

Your doctor can determine the severity of exercise intolerance through various methods, including semi-quantitative assessments and qualitative methods.

Semi-qualitative assessments involve your doctor interviewing you to evaluate the extent of your intolerance.

Qualitative methods involve timed walking tests and graded exercise treadmill or bicycle exercise tests. These methods offer the most accurate and reliable evaluation of exercise tolerance. They also yield multiple vital outcomes, including exercise time, exercise workload, and metabolic equivalents.

You may be tempted to avoid working out when you have this condition, but giving up should not be the last resort. Consider the following options when exercise intolerance sets in.

  • Supervised workout sessions. Studies have shown that supervised aerobic activities can improve exercise capacity.
  • Oxygen supplementation. Also known as oxygen therapy, it's a treatment that delivers oxygen gas for you to breathe. Oxygen supplementation during exercise in people with exercise intolerance results in improved exercise endurance and breathlessness. The therapy can be given for a short or long period in the hospital or at home.
  • Administration of bronchodilators. A bronchodilator is a type of drug that relaxes the muscle bands that tighten your airflow. These alleviate bronchial obstruction and airflow limitation, reduce hyperinflation, and improve exercise performance.
  • Adopt lighter exercises. It would be helpful to change your routine of working out as opposed to abandoning it altogether.