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Why Do I Have Dizzy Spells While Working Out?

Contributor Caroline Schepker, DO
7 minute read
A woman looking dizzy after working out.

An intense exercise session may leave you feeling worn out. But if you feel like you have dizzy spells after exercise, take some time to really think about the symptom. Would you describe it as dizzy or lightheaded? Ask yourself: Did you overdo it? Did you have enough to eat or drink beforehand?

“It's important to understand that there’s a difference between dizziness and lightheadedness. Many people say they feel dizzy when they really mean they feel lightheaded,” says Caroline Schepker, DO, a Mass General Brigham sports medicine physiatrist who treats patients at Wentworth-Douglass Hospital. “The possible cause depends on whether you’re truly dizzy versus actually lightheaded.”

Dizziness feels more like vertigo or imbalance, perhaps like the room is spinning, she explains. It may be accompanied by trouble moving your eyes normally. Lightheadedness—which is much more common during and after exercise—is the sensation of feeling faint. Perhaps you “see stars” or feel like you might pass out.

“Even if you feel just a bit lightheaded and you think it’s from a reversible cause such as overexertion or dehydration, you should speak with your primary care provider about it. They can help you determine what happened and give you tips to prevent it in the future,” Dr. Schepker says. “They can also make sure to catch anything that might be more serious.”

Dizzy spells while working out

If you’re experiencing true dizziness, you should seek medical treatment. Common causes of dizziness include:

Lightheadedness when working out

However, most people who say they are having a dizzy spell really mean they’re lightheaded, Dr. Schepker says. There are many common reasons this can occur when you work out, but most are easily reversible or preventable.

Poor conditioning or overexertion

The top reason for lightheadedness during exercise is poor conditioning or overexertion.

“It’s common to feel lightheaded if you take on more than your body is conditioned to handle—in other words, if you increase your exercise workload or intensity too much, too soon,” she says. “Whenever starting new exercise programs or increasing the intensity or duration of an existing exercise regimen, it should be done gradually.”

For example, runners should not increase distance by more than 10% to 20% per week. With other types of exercise, it’s generally safe to boost intensity or duration by up to 25% per week.


Another common cause of lightheadedness during workouts is not drinking enough water throughout the day.

“The best way to prevent dehydration is constant attention to your hydration throughout the day, every day, because that’s how the body holds on to fluid best. Drinking periodically throughout the day is much better than drinking a whole bunch of water right before a workout,” Dr. Schepker advises. “Drinking too much water at once can overwhelm the kidneys, and you can end up excreting more than you retain.”

She recommends a minimum of 64 ounces (up to about 100 ounces) per day for the average adult. Those who exercise heavily and sweat more may want to go as high as 120 to 150 ounces. Anything more than that has the potential to come with risks, she warns, so don’t overdo it and listen to thirst signals.

Many avid exercisers and athletes consume electrolyte-replacement drinks. But Dr. Schepker recommends them only when exercising for more than 90 minutes or working out in a very hot environment. “Otherwise, for the typical exercise session in a climate-controlled environment like a gym or in a reasonable outdoor temperature, if it’s under 90 minutes, plain water is just fine.”

Certain people might have to pay closer attention to hydration than others. For example, in the later stages of pregnancy, the body isn’t as good at cooling itself. So pregnant people might need extra fluid during exercise. Older adults are less likely to have a good thirst signal. Therefore, they might need to be a little more proactive about remembering to drink fluids. Finally, children often forget to hydrate. So parents and coaches should make sure that fluids are available and that kids use them, especially on hot days.

Get more hydration tips for athletes.

Improper breathing

“When we’re exercising and we’re short of breath, which is normal, and we’re also very engaged in what we’re doing, we can sometimes neglect to really take good, deep breaths,” Dr. Schepker says. “A lot of us tend to use the wrong muscles to take deep breaths. Or we may hold our breath during periods of intense exertion.”

Take deep breaths throughout your entire workout. Instead of using muscles in your chest and neck to breathe, she suggests engaging your diaphragm.

Less common reasons for episodes of lightheadedness

There are less common causes that are more serious, Dr. Schepker says. That’s why it’s important to talk to your primary care provider if you have an episode. This is particularly important if you experience other symptoms, such as chest pain or confusion.

Other less common causes of lightheadedness during exertion include:

  • Cardiovascular issues, such as low blood pressure, uncontrolled high blood pressure, or arrhythmia
  • Low blood sugar—usually only in people with diabetes or endurance athletes (such as those who do triathlons and marathons)
  • Neurological conditions such as postural tachycardia syndrome (also called POTS) or stroke
  • Heat exhaustion or heat stroke, serious conditions that can occur during exercise in a very hot or humid environment. Learn how to stay safe exercising in the heat.
  • Underlying infection
Prevention is key here. Get adequate hydration throughout the day, not just right before exercise. Build up your exercise intensity slowly. Make sure you get enough nutrition and calories throughout the day.

Caroline Schepker, DO
Sports Medicine Physiatrist
Mass General Brigham

What should I do if I feel lightheaded when working out?

If you feel dizzy or lightheaded during exercise:

  • Sit down or lie down to avoid falling.
  • Try elevating your legs above the level of your heart.
  • Drink some water.
  • Have a snack.
  • Put a cool cloth around your neck or on your forehead.
  • Think about whether you’re having other symptoms that might indicate an emergency, such as chest pain, palpitations, or slurred speech.

“Prevention is key here. Get adequate hydration throughout the day, not just right before exercise. Build up your exercise intensity slowly. Make sure you get enough nutrition and calories throughout the day,” Dr. Schepker says. “It’s also important to have regular visits with your primary care provider for preventive care. If you attend to your health on a regular basis, you’re more likely to avoid any events.”

Learn about Mass General Brigham Sports Medicine services


Sports Medicine Physiatrist