Fatigue After Exercise – What You Should Know

Exercise, along with proper diet and sleep habits, is important for healthy living. It is also one way to beat fatigue, though sometimes it has the opposite effect. In some cases, fatigue after exercise lingers longer than a few hours, often lasting for days. Post-workout exhaustion may result from poor nutrition, lifestyle choices, or medical conditions, so determining the cause is also important for recovery.

Though you may experience mild fatigue, sometimes the issue is more concerning. For instance, if you’re a senior or think you may have a neurological condition, seeking medical advice is vital. You may have an underlying condition causing your exhaustion. To learn more about extreme fatigue after workouts, keep reading.

Therapist and elderly woman playing with yoga ball to prevent fatigue after exercise.

Possible Causes of Fatigue After Exercises

Feeling tired after physical activity is normal and usually fades after a few hours of rest. If the exhaustion lasts a day or more, the issue may be more severe, with several possible causes.


Physical activity and exercise should be part of your routine, but it’s also crucial to rest between sessions to prevent fatigue. In fact, resting your muscles for 24 to 48 hours is recommended after a vigorous workout. Otherwise, you may develop overtraining syndrome, often affecting brain function, the immune system, and other body systems. You may also be pushing yourself beyond your limits, increasing your risk of injury.


Sweating during physical activity is normal, but if you aren’t hydrating, losing those fluids may be more harmful than expected. Excessive fluid loss causes dehydration, a common cause of fatigue after exercise. Other symptoms include thirst, dry skin, dizziness, and infrequent urination, while severe cases cause fainting, rapid heart rate, and shock.

Poor nutrition

Your body needs fuel to keep working hard, especially during physical activity. When lacking the proper nutrients, the glycogen your muscles use for energy is spent too quickly. The result is low blood sugar or hypoglycemia, which causes fatigue, headaches, sweating, confusion, and nausea. These symptoms persist and may increase in severity if blood sugar levels aren’t restored.

Medical conditions

Those battling a temporary or chronic medical condition, including Parkinson’s, MS, cancer, diabetes, or heart disease, often suffer from fatigue. Such illnesses force the immune system to work harder as it tries to heal the body. Even many of the medications or treatments for such conditions increase tiredness.

Adding physical activity to the mix often improves blood flow and strength. Unfortunately, after you exercise, fatigue may also increase. Before adding new workouts to your day, speak to your doctor about safe routines for your condition.

When is fatigue after exercise worrisome?

Short-term fatigue after physical activity is often reduced with rest, plenty of water, and a good meal. But sometimes, these aren’t enough, and the exhaustion becomes unmanageable, even after a good night’s sleep. You may even notice new symptoms, such as confusion, nausea, pain, difficulty breathing, confusion, or heart palpitations.

If your fatigue after exercise lasts several days or any new symptoms appear, speak to your doctor. A medical professional will then determine the cause of the issue and recommend a treatment to reduce your exhaustion.

This article is for educational and informational purpose only and does not substitute for professional medical advice. For any questions about your own health condition, speak to a qualified physician or healthcare provider.