An active lifestyle is an integral component of good health and well-being. Doctors advise us to increase physical activity levels to stay healthy and manage various medical conditions. Physical activity such as exercise usually resurfaces positive emotions and people feel energetic afterwards. However, some people feel nauseous and experience discomfort due to exercise intolerance. In this post, you’re going to learn more about this problem and how to manage it. Read on to find out more.

What is Exercise Intolerance?

Exercise intolerance (EI) is the inability or reduced ability to perform physical activities at the normal or expected level for a person’s size or age. However, EI is not the same as decreased stamina, strength, or motivation. Symptoms of EI can be debilitating and occur due to underlying health problems.

A person with low fitness levels can slowly build their strength, but someone with EI finds it challenging to do so.

When left unmanaged, EI can decrease a person’s quality of life. Intolerance to exercise deprives people of enjoying various activities or having fun. People with EI find it difficult to sustain or complete exercises that would typically be within their physical capacity. If you’re ever wondering with the question, “Why do I feel nauseous after working out?”, EI could be the main culprit.

What are the symptoms of exercise intolerance?

The primary sign of exercise intolerance is a consistent inability or difficulty to participate in reasonable levels of physical activity. That said, the exact signs may vary from one person to another depending on their overall health and the underlying cause. Below are some of the most common symptoms and changes you may experience due to EI:

  • Chest pain and discomfort: you may notice pain and discomfort in your chest as well as your left arm, neck, and back. Pain and discomfort may occur during or after a workout, especially when performing strenuous activities such as bench press or weightlifting.
  • Unusual and severe shortness of breath: difficulty breathing beyond what is considered normal during exercise. This happens when there’s not enough oxygen passing into your lungs.
  • Excessive sweating: you may experience abnormally high levels of perspiration during and after exercise due to heat intolerance. Sweating too much could indicate the presence of an underlying health problem too.
  • Discoloration of the skin: during and after exercise, you may notice changes in the skin. These changes appear in the form of purplish, bluish color, and flushing. Sometimes skin appears paler or darker than usual.
  • Leg cramps and muscle pain: this symptom is quite common, especially in more mature men and women. Cramps go away quickly but can be bothersome. In addition to nausea after working out, cramps and pain can be overwhelming and affect a person’s motivation.
  • Severe fatigue: you may feel like it’s difficult to perform even the easiest movements due to lack of energy. Fatigue is persistent and keeps worsening while you’re working out. Sometimes people experience dizziness, shortness of breath, and fatigue, which could indicate a low oxygen supply.

What causes exercise intolerance?

Intolerance to exercise results from breathing difficulties after a short physical activity. Low oxygen supply causes fatigue to the point you can’t tolerate movement. Sometimes it contributes to nausea and sleep deprivation. In many cases, EI stems from underlying health problems. Common causes of EI are listed below:

  • Respiratory conditions: asthma, lung cancer, and COPD (chronic obstructive pulmonary disease) make it challenging to get a sufficient amount of oxygen due to decreased ability to breathe. The severity of EI depends on the severity of these conditions.

  • Chronic fatigue syndrome: leads to a consistent lack of energy that doesn’t improve with sleep. Post-exertional malaise (PEM) and EI are hallmark symptoms[1] of chronic fatigue syndrome.

  • Diabetes: it affects how the body uses glucose (blood sugar), which gives cells the energy necessary for their functioning. People with type 2 diabetes may develop EI[2] independently of other factors such as cardiovascular problems. This could explain why you feel the nausea after working out.
  • Heart failure: any problem that affects the heart’s ability to pump blood can contribute to the development of EI. Evidence shows[3] that EI shares some features of classic respiratory and cardiac disorders. What’s more, EI is a major symptom of chronic heart failure, which results from the inability to pump blood around the body.
  • Motor neuron disease: with time, diseases such as multiple sclerosis weaken muscles and cause persistent fatigue and difficulty moving.
  • Post-viral fatigue: sometimes, people experience tiredness and weakness for weeks or months following a viral infection such as COVID-19. That’s why you may feel sleepy aftera workout even if your exercises aren’t that vigorous.
  • Injuries: you may develop EI due to injuries that affect muscle fibers, nerves, joints, or tendons.
  • Muscle fiber failure: problems in cells can lead to muscle fiber failure due to lack of energy.

How to manage exercise intolerance

Treatment of exercise intolerance depends on the underlying cause. See a doctor if you experience symptoms of EI. They will order necessary tests to determine the cause unless you’re already diagnosed with a certain health problem. Identifying the cause of EI helps shape the treatment approach. In most cases, it includes the following:

  • Identifying how much exercise you can tolerate
  • Reducing energy output by adapting how you move
  • Planning tasks ahead of time so they don’t become strenuous
  • Increasing physical activity levels when it feels safe (listen to your body)
  • Using dietary supplements such as Nuu3 Nature’s Superfuel to increase your energy levels
  • Working out under supervision
  • Eating a healthy diet
  • Staying hydrated throughout the day
  • Getting enough sleep
Eating a healthy diet

Frequently Asked Questions

How do you fix exercise intolerance?

You can fix exercise intolerance by gradually increasing physical activity levels to allow the body to adapt. Consult hiring a personal trainer who will customize a workout plan based on your needs and current fitness level. It’s also useful to see a doctor to manage underlying health problems. A healthy lifestyle can be of huge help in managing this problem.

What deficiency causes exercise intolerance?

Deficiency in vitamin D could contribute to intolerance to exercise because the sunshine vitamin plays a key role in muscle contraction. Low levels of vitamin D[4] can contribute to fatigue, muscle pain, weakness, and reduced athletic performance. If you feel sleepy after the workout, insufficient vitamin D could be the problem.

Is exercise intolerance reversible?

With appropriate management, exercise intolerance can be reversible. For that reason, it’s crucial to identify and address underlying causes, such as nutritional deficiencies and medical conditions. Work actively on increasing fitness levels, and improvements will come.


Exercise intolerance results from a wide range of causes, some of which can be serious while others are not. It’s important to identify the cause of EI to manage and potentially reverse this problem. Supervised workouts can be of huge help. However, you don’t want to push yourself too hard, so make sure you know your limits and always listen to your body.