Have you ever finished a workout only to feel like the room is spinning? That dizzy, unsteady feeling known as lightheadedness is common after exercise. While often harmless, it can be concerning, especially for people with heart conditions.

According to Cleveland Clinic, dizziness during or after physical activity affects many people and can have various causes. For those with heart disease, these symptoms might need extra attention as they could signal more serious issues.

Let’s explore seven common causes of dizziness and lightheadedness after working out and some tips that may help.

1. Dehydration

Not drinking enough water is one of the most common causes of lightheadedness after a workout. When you sweat during exercise, you lose fluids that you need for your body to function properly. Without enough fluids, your blood pressure can drop suddenly, making it harder for your heart to pump blood effectively throughout your body — including your brain.

If you have heart disease, staying hydrated is even more important. Dehydration puts extra strain on the heart, forcing it to work harder.

Try to drink water before, during, and after your workout. Sports drinks can help replace electrolytes lost through sweating during intense exercise.

After working out, you can also try to eat snacks that have high water content, like fruits and vegetables, to maintain your hydration.

2. Dropping Blood Pressure

Standing up too quickly after exercising can cause sudden blood pressure drops, leading to dizziness. This is called postural or orthostatic hypotension.

When you stand up, gravity pulls blood into your legs, and your blood pressure begins to fall. Normally, your body compensates by sending signals to your heart to beat faster and to your blood vessels to constrict, preventing your blood pressure from falling too much.

For those with heart conditions, medications like beta-blockers or diuretics can increase the risk of this phenomenon. Heart valve problems, a history of heart attacks or heart failure, and bradycardia (extremely low heart rate) are also risk factors.

Taking your time when changing positions may be helpful. Sit up slowly before standing, and stand for a moment before walking.

3. Low Blood Sugar

Your muscles use glucose (sugar) for energy during exercise. If you work out without eating enough beforehand or exercise for an extended period, your blood sugar levels can drop too low. Hypoglycemia (low blood sugar) can make you feel dizzy, nauseous, anxious, and shaky. People taking certain diabetes medications may be particularly likely to experience hypoglycemia.

Those with heart disease need to be especially careful about blood sugar levels, as the stress of hypoglycemia can trigger heart problems like arrhythmia (problems with your heart beat), heart attack, and heart failure.

Before a workout, opt for a light meal or small snack, particularly one that includes protein and carbohydrates. This can help prevent the drop in blood sugar. For more intense workouts, such as weight lifting or longer exercises over an hour, you may need to eat a meal within an hour of finishing.

4. Overexertion

Pushing yourself too hard during a workout can lead to lightheadedness, especially if you’re not used to intense exercise. When you exercise beyond your fitness level, your heart and lungs sometimes can’t keep up with the body’s demand for oxygen. Not having enough oxygen may make you feel dizzy and weak.

For those with heart conditions, overexertion and constant high-intensity training can increase the risk of cardiac arrest (when your heart stops beating) and heart rhythm disorders. The risk is especially high for people who have coronary heart disease, heart failure (cardiac weakness), and hypertrophic cardiomyopathy ( a genetic condition that causes the left ventricle of the heart to become thick and stiff).

5. Poor Breathing Techniques

Proper breathing techniques during exercise are extremely helpful. It’s normal to breathe faster during exercise because your body needs more oxygen. You may experience lightheadedness, dizziness, muscle cramps, and even fainting if you breathe too fast with deep breaths outside of physical activity (also known as hyperventilation, usually due to stress or anxiety).

In this situation, the problem is not the low oxygen level — it may be even higher than needed. These symptoms happen when you breathe out too much carbon dioxide, which lowers the acid in your blood. This can throw off the balance of important minerals like potassium and calcium.

To feel better, try to stay calm and do pursed-lip breathing — breathe out slowly through puckered lips, like you’re blowing out a candle. This helps keep carbon dioxide from dropping too low.

Regularly exercising can make your heart and lungs more efficient at moving oxygen throughout your body, reducing your chances of becoming short of breath. Remind yourself to keep taking deep breaths and keep a steady, even breathing rhythm throughout your entire workout.

6. Heart-Related Issues

Lightheadedness, in general, can signal underlying heart problems. This is especially important for those already diagnosed with heart disease. Exercise puts additional demands on your heart. If your heart can’t meet these demands due to disease or damage, you may have symptoms like lightheadedness, shortness of breath, or chest pain.

Dizziness and lightheadedness can be symptoms of arrhythmias, valve disease, heart attack, stroke, or cardiomyopathy.

If you have heart disease and experience dizziness or frequent lightheadedness with or without exercise, talk to your cardiologist (heart doctor). They might adjust your medications or recommend specific exercises that are safer for your condition.

7. Medication Side Effects

Many medications, particularly those prescribed for heart conditions, can cause dizziness as a side effect. Diuretics, or medications that make you urinate frequently, and medications that lower your blood sugar most commonly cause lightheadedness. This effect may be more obvious during exercise.

Common heart medications that might cause lightheadedness include:

• ACE inhibitors
• Beta-blockers
• Calcium channel blockers
• Diuretics (water pills)
• Nitrates

If you feel dizzy during exercise, talk to your doctor about your medications. Don’t stop taking any prescribed medicine unless your doctor tells you to.

When To Seek Medical Attention

While occasional mild lightheadedness after exercise is usually not serious, certain symptoms warrant immediate medical attention. You should seek emergency care if your dizziness is accompanied by:

• Chest pain, pressure, or tightness
• Shortness of breath
• Irregular heartbeat
• Fainting or loss of consciousness
• Severe headache that comes on suddenly
• Confusion or trouble speaking
• Weakness or numbness, especially on one side of the body
• Falling or inability to walk
• Persistent vomiting
• Seizures

For people with heart disease, these symptoms could indicate a serious cardiac problem requiring quick medical care.

How To Prevent Lightheadedness After a Workout

To reduce the risk of lightheadedness after you work out:

• Stay hydrated before, during, and after exercise.
• Warm up properly before exercise and cool down afterward.
• Slowly make your workouts harder over time.
• Monitor your heart rate during exercise.
• Eat a small snack beforehand.
• Take breaks when needed.

For those with heart disease, these additional steps can help keep you safe:

• Always follow your doctor’s exercise recommendations.
• Be mindful of exercising during weather that’s too hot or cold.
• Carry emergency contact information and a list of your medications.
• Consider cardiac rehabilitation programs for supervised exercise.
• Continue to take your medications as prescribed.

Remember that staying active is important for heart health, but safety comes first. With proper precautions and awareness, most people — even those with heart conditions — can enjoy the benefits of regular physical activity without concerning symptoms.

Talk With Others Who Understand

On MyHeartDiseaseTeam, the social network for people living with heart disease and their loved ones, more than 62,000 members come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

Do you experience lightheadedness after working out? Do you have any tips to reduce feelings of lightheadedness or dizziness? Share your tips and experiences in a comment below or start a conversation on your Activities page.