You have just concluded an exercise session when you begin to feel dizzy and lightheaded as if you might faint. As your heart beats faster, you wonder if this is a common occurrence after exercise or a sign of something more serious. Understanding why you experience lightheadedness and how to prevent and treat it can reduce this occurrence.
If you have not eaten in a long time period, you may feel lightheaded after exercise due to low blood sugar. Intense exercise can cause your blood pressure to drop, which can make you feel lightheaded, according to Up to Date. Also, if you do not have a sufficient amount of fluids in your system, your body may begin to sweat excessively. This sweat results in the loss of electrolytes needed to maintain fluids and causes your heart to beat faster—this causes you to feel hotter and potentially lightheaded.
Certain groups of people may be more likely to experience lightheadedness and other adverse effects from strenuous exercise, according to The New York Times. These include those with uncontrolled high blood pressure, diabetes, unstable angina, a history of heart attack or other serious heart conditions. If you have been sedentary for an extended period of time, take caution when engaging in strenuous exercise.
Eating a snack before exercising or a meal three to four hours before exercising can help prevent lightheadedness. Drink water before, during and after your workout to prevent dehydration. Post-workout, perform cool-down exercises. Spend five minutes after your workout by slowing your heart rate through slow walking and stretching, according to Up to Date. This time also reduces the amount of acid built up in the body's cells that were released during exercise. As a result, more blood is allowed to circulate. This prevents the drop in blood pressure that can lead to post-workout lightheadedness.
If you do experience lightheadedness following a workout, lay down and keep your head level with your heart—do not allow your head to drop below your heart, according to Go Ask Alice, a health and wellness resource from Columbia University. This will help to restore blood flow to the brain, helping to reduce lightheadedness. As you begin to feel better, drinking an electrolyte-containing drink to restore fluid balance or eating a banana or crackers can help to incorporate minerals into your body.
While lightheadedness after a workout typically is not cause for concern, in some instances, it can indicate a more serious condition, according to Go Ask Alice. For example, if you take preventive steps to reduce lightheadedness post-workout, yet still experience lightheadedness, seek medical attention. Your physician may recommend alternate exercises and perform diagnostic tests to examine your heart, blood pressure and lung function.