What is Exercise Intolerance?

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

It's associated with heart disease because the heart fails to pump blood properly when exercising. You may also experience the condition if you have mitochondrial disease and metabolic disorders.

Symptoms of Exercise Intolerance

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 exercises. 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.

Causes of Exercise Intolerance

Exercise intolerance happens 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.

Continued

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

You are also likely to develop exercise intolerance 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 lead to exercise intolerance.

Diagnosis of 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.

Management of Exercise Intolerance

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.
WebMD Medical Reference Reviewed by Dan Brennan, MD on June 15, 2021

Sources

SOURCES:

The American Journal of Cardiology: “Effects of Oral Magnesium Therapy on Exercise Tolerance, Exercise-Induced Chest Pain, and Quality of Life in Patients with Coronary Artery Disease.”

Breathe: “Common causes of dyspnoea in athletes: a practical approach for diagnosis and management,” “Treatment burden of respiratory conditions.”

Centers for Disease Control and Prevention: “Work-Related Musculoskeletal Disorders & Ergonomics.”

Circulation: “Exercise and Heart Failure. A Statement from the American Heart Association Committee on Exercise, Rehabilitation and Prevention.”

Heart failure clinics: “EXERCISE INTOLERANCE.”

Indian Journal of Dermatology: “Acryocyanosis: An Overview.”

Journal of Cardiopulmonary Rehabilitation and Prevention: “Pathophysiology of Exercise Intolerance and its Treatment with Exercise-Based Cardiac Rehabilitation in Heart Failure with Preserved Ejection Failure.”

Journal of the American College of Cardiology: “Exercise Intolerance in Patients with Heart Failure: JACC State-of-the-Art Review.”

National Heart, Lung, and Blood Institute: “Oxygen Therapy.”

National Institute of Neurological Disorders and Stroke: “What are mitochondrial myopathies?”

Neuromuscular Disorders: “Fatigue and exercise intolerance in mitochondrial diseases. Literature revision and experience of the Italian Network of mitochondrial diseases.”

Physiological Genomics: “Genes and exercise intolerance: insights from McArdle disease.”

Physiological Reports: “The effects of exercise and passive heating on sweat glands ion reabsorption rates.”

Sports Health: “Exercise-Associated Muscle Cramps.”

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