Feeling dizzy after a workout is a common occurrence. Often, it is the result of something minor, such as mild dehydration.
In other instances, however, it can indicate an underlying condition that requires treatment.
In this article, we list seven potential causes of dizziness after exercise, and we discuss treatments and methods of prevention.
Possible reasons for feeling dizzy after a workout include:
Overexertion occurs when people push themselves too hard during physical activity. Signs of overexertion include:
- feeling faint
- shortness of breath
According to 2015 research, injuries related to overexertion account for 36.2% of all injuries occurring at fitness facilities.
Overexertion does not just happen in gyms or exercise classes, however. It can happen during any activity.
2. Use of continual motion machines
The type of exercise a person does may influence whether they feel dizzy. For example, using an elliptical machine or a treadmill, which both involve continuous movement, is more likely to cause dizziness.
Some people experience lightheadedness or dizziness when they step off the machine. They may feel like they are still moving when they are not.
This experience is called vertigo. Others experience dizziness as a symptom of motion sickness.
Dehydration occurs when the body loses more water than it takes in. Although dehydration is most common in children and older adults, it can affect people of any age.
Healthy adults are most likely to experience dehydration from a minor illness or intense physical activity, especially during hot weather.
Symptoms of dehydration include:
- dry mouth
- extreme thirst
- feeling faint or lightheaded
- less frequent urination
Even mild dehydration, which is a loss of just 1–2% of body weight, can cause these symptoms. Many people think that thirst is one of the first signs of dehydration, but by the time someone feels thirsty, they are already experiencing dehydration.
4. Lack of oxygen
Improper breathing during exercise means that some people do not take in enough oxygen to meet the needs of their muscles.
During exercise, muscles use more oxygen than usual. This is why heart rate and breathing become faster to facilitate a higher intake of oxygen.
People who do not breathe often enough or deeply enough can experience a lower-than-optimal level of oxygen in the brain. Dizziness is a sign that the brain requires more oxygen.
5. Low blood pressure
Blood pressure is the force of the blood that pushes against the artery walls. In most people, healthy blood pressure is less than 120/80 millimeters of mercury (mm Hg). People who have low blood pressure, or hypotension, will have a reading of less than 90/60 mm Hg.
Blood pressure is typically at its lowest within an hour of exercise. Some people may notice a more sudden drop, however.
In addition to dizziness, symptoms of hypotension include:
- blurred vision
- loss of concentration
Vigorous activities most often cause low blood pressure, although any activity can trigger it. Some people with hypotension feel symptoms simply if they stand up too quickly.
Hypotension can be a cause of exercise-induced dizziness during pregnancy. It also results from dehydration, heart problems, and the use of certain medications.
6. Low blood sugar
Hypoglycemia, or low blood sugar, occurs when the level of glucose (sugar) in the blood is very low.
Sugar is the body’s primary energy source. During exercise, the muscles use more glucose than usual. As a result, some people experience low blood sugar during or after physical exertion.
Symptoms of hypoglycemia include:
People may be more likely to experience hypoglycemia if they have not eaten much before exercising. This can be a common problem for those who exercise first thing in the morning.
7. Heart arrhythmia
A heart arrhythmia is an abnormal heartbeat. Arrhythmias may cause the heart to beat too quickly, too slowly, or irregularly. Many conditions can cause arrhythmias, including heart conditions and emotional stress.
Not all arrhythmias cause symptoms, but when symptoms do occur, they include:
- change in heartbeat
- shortness of breath
Even when symptoms occur, it does not necessarily mean that a person has a serious problem. However, it is always important to see a doctor for persistent arrhythmias.
The treatment for feeling dizzy after a workout depends on the underlying cause of the problem.
In some cases, treatment is simple and straightforward. In others, it may be necessary to see a doctor for further investigation and medical attention.
Rest and breathe
When dizziness occurs as a result of overexertion, improper breathing, or low blood pressure, people can try the following:
- Cool down and rest for a few minutes.
- Sit down and place the head between the knees, which increases blood flow to the brain.
- Practice deep breathing for several minutes, making sure to inhale and exhale slowly.
- When exercising, consciously practice breathing in and out in a regular rhythm.
When dizziness occurs while using a treadmill or other machine that uses continual motion, people should hold tightly to the rails and slow down their pace until it is safe to stop. These actions may prevent dangerous falls.
Avoid walking around or driving until dizziness subsides.
The only treatment for dehydration is to replace fluids and electrolytes. For most people, drinking water or a sports drink will resolve symptoms.
Some people may need an over-the-counter oral rehydration solution, which contains water and electrolytes.
People should drink enough fluid during the day so that their urine is pale yellow. If exercising during very hot or humid weather, try to drink chilled fluids to help cool down. The body absorbs cool fluids better than warmer ones.
To avoid dehydration in the future, people should sip fluids all day before, during, and after exercise. Drinking small amounts frequently is typically better than drinking large amounts less often.
Severe dehydration requires medical attention.
Drinking a glass of fruit juice may provide faster relief from the symptoms of hypoglycemia.
However, it is a good idea to follow this up with a meal or a snack containing whole grains and proteins to avoid another blood sugar crash.
If symptoms persist or recur despite taking steps to stop feeling dizzy after exercise, it may be necessary to speak to a doctor.
A doctor can check for an underlying reason for the dizziness, such as:
- heart problems, including arrhythmia
- severe dehydration
- severe hypoglycemia
They may prescribe medications or medical treatments for diabetes and heart problems. In cases of severe dehydration or severe hypoglycemia, it may be necessary to receive urgent treatment with intravenous fluids or intravenous glucose.
The following tips may reduce the risk of experiencing dizziness after a workout:
- increasing the intensity of workouts gradually
- avoiding pushing the body too hard
- practicing regular breathing during exercises
- considering doing Pilates or yoga, as these activities can teach people how to regulate their breathing
- drinking plenty of fluids before, during, and after workouts
- having a snack of complex carbohydrates and lean proteins an hour or so before a workout
- quitting smoking
If the dizziness persists, people must see their doctor. A doctor can investigate the problem and check for underlying health conditions.
Individuals should seek urgent medical care if they suddenly or frequently experience the symptoms of a heart arrhythmia.
It is also necessary to seek urgent care for severe symptoms of other conditions, such as:
- confusion and disorientation
- extreme fatigue
- inability to keep down fluids
- loss of consciousness
Often, feeling dizzy after a workout is not a serious cause for concern. It usually indicates that someone is overexerting themselves or has not had enough to eat or drink before exercising.
If dizziness only occurs when using a treadmill or similar machine, it can suggest vertigo.
Occasionally, feeling dizzy after a workout may mean that a person has low blood pressure, especially if they are pregnant. Less commonly, dizziness after exercise indicates a heart problem or diabetes.
Individuals who experience frequent or severe dizziness should see a doctor.