Lightheaded When Lifting Weights? Here's What Your Body's Trying to Tell You

Lifting weights — especially intensely, like in bodybuilding — places a lot of stress on your body. Heavy weights that cause you to strain more than normal can affect your blood pressure and heart rate, leaving you feeling lightheaded.

It's usually temporary and nothing to worry about, but you should talk to a doctor if you're consistently lightheaded or dizzy when you lift heavy objects.

Here are some of the common causes of lightheadedness while lifting weights, what to do about them and when to see a doctor.

Feeling momentarily lightheaded during or after an intense strength-training workout is not uncommon. The sensation comes from the increased strain placed on your heart when lifting heavy weights, which affects your blood pressure, according to December 2012 research in ‌BMC Public Health‌.

Many lifters hold their breath as they push or pull a heavy weight at the beginning of an exercise. The lack of oxygen intake while performing a strenuous action almost instantaneously causes the heart to beat faster, leading to higher blood pressure. The heart does this to deliver the oxygen the body needs to complete the action to the muscles that are working hardest.

Good breathing technique can help you control feelings of lightheadedness. If you lift heavy weights that cause you to strain, force yourself to breathe normally throughout the movement. Exhale through the top of the movement, then inhale as you return to the starting position.

Dehydration can also contribute to lightheadedness, according to the Cleveland Clinic. While you're more likely to lose a lot of fluids through a cardio workout than through strength training, if you start lifting when you're already dehydrated, you could feel dizzy, weak and lightheaded during exercise.

Drink plenty of water before, during and after a workout to keep yourself hydrated. Look for pale yellow urine as a sign you're optimally hydrated, per the Cleveland Clinic. And try to drink throughout the day, even before you're thirsty, which is actually a sign of mild dehydration.

If you sit or stand up too quickly, you may experience orthostatic hypotension — a dramatic drop in your blood pressure — which results in lightheadedness, according to the Mayo Clinic. This could happen after lifting weights lying down on a bench, for example, and it could even cause you to faint.

If you're generally healthy, orthostatic hypotension may be fleeting: Sit back down for a moment and wait for the sensation to pass.

If the feeling lingers or happens frequently or if you do actually faint, it's time to talk to a doctor, per the Mayo Clinic. You could have overall low blood pressure that's contributing to the lightheaded sensation while lifting weights.

The lightheaded feeling during a workout typically passes after a few seconds. If, however, you consistently experience dizziness and feel lightheaded for more than several seconds after an exercise, speak with your doctor.

This could be a sign of a more serious underlying condition that gets worse by straining when lifting weights. Heart conditions such as arrhythmia and cardiomyopathy can cause the heart to pump inadequate amounts of blood through your body, according to the American Heart Association.

If you routinely feel lightheaded while lifting weights and it's not because you're holding your breath or standing up too fast, talk to your doctor about your symptoms. They may want to do some tests to evaluate the overall health of your heart.

And if you know you have any heart-related health concerns, speak with your doctor before beginning a strength-training regimen.