Why do people faint while deadlifting?

We've all seen videos of someone trying to break a personal record in the deadlift, only to collapse during or after the set. Although such videos are widely shared, fainting during the deadlift isn't common, and preventing it is a matter of understanding why it happens.

People faint during deadlifts for the following reasons:

In this text, we will look at each of these items in more depth so that you don't run the risk of fainting when doing deadlifts or even minimize dizziness during this and other heavy weight training exercises.

Syncope is the medical term for a temporary loss of consciousness – commonly known as “fainting” – usually caused by a lack of blood flow to the brain.

It is relatively common to use the valsalva maneuver when deadlifting.

This breathing method involves taking a deep breath, holding it, and then forcefully pushing it out. When you "push out," you're actually still holding your breath, but mimicking the sensation you'd get if you were to exhale.

This maneuver makes your spine more stable and helps during exercise by creating intra-abdominal pressure, allowing your core to be stabilized as if you were wearing a back belt.

However, during the Valsalva maneuver, your blood pressure increases. After completing the maneuver, your blood pressure decreases, often below normal, before rising again and returning to normal. This fluctuation occurs rapidly, and it's the sudden drop in blood pressure that can make you feel dizzy.

The Valsalva maneuver is a legitimate weightlifting technique, but it can go wrong in the following scenarios:

When you perform the valsalva maneuver, as soon as you feel your core/abs engaged, you should begin lifting the weight off the floor.

The longer you hold your breath, the longer your brain will be deprived of oxygen. You also don't need to hold your breath throughout the entire movement. A good practice is to exhale as soon as you reach the top.

Your blood pressure rises when you perform the valsalva maneuver, but when you exhale, your blood pressure decreases. This is normal, as you want your blood pressure to return to normal.

However, if you exhale too quickly, there will be a sudden drop in blood pressure, often overcompensating and temporarily dropping below normal levels.

Try to remember to exhale in a controlled manner once the lift is complete.

While the Valsalva maneuver can cause a sudden drop in blood pressure, there are other factors that can facilitate the problem.

If you sit for a long time and then stand up, your blood often pools in your lower extremities (legs), which can cause your blood pressure to drop.

Before attempting a heavy set of deadlifts, it's a good idea to stand or walk around for a minute or so to avoid this problem.

If you are performing high-intensity physical activity with little water in your body, your blood pressure may drop during moments of maximum exertion.

These days, it's unusual to see someone training without drinking enough water, but it can happen in a specific situation.

The day after drinking alcohol, you're more likely to experience drops in blood pressure. This will be even more pronounced if you've had too much the day before (i.e., if you're hungover).

Once you've gained some experience with deadlifting, you understand that setup—the initial positioning to grip the bar—is important. However, some people, out of zeal, may overdo it and take a long time getting into position.

When you're bent over holding the barbell, blood rushes to your head. When you start pulling the load and stand up straight, blood quickly drains from your head to facilitate oxygen delivery to your leg and back muscles.

This is normal, but what you want to avoid is leaning over for too long and accumulating too much blood in this position, causing all your blood to go to your head and then quickly rush to your muscles to facilitate movement, potentially making you dizzy or faint.

This effect can be further aggravated by the wrong Valsalva maneuver and some of the other errors already discussed, such as holding the breath for too long or exhaling too quickly.

If you train with low blood sugar (low blood glucose), you may be at greater risk of fainting while deadlifting.

This usually happens when you try to train in a fasted state or have recently started a low-carb diet.

Additionally, you may be forced to reduce carbohydrates if you're an athlete trying to make your weight class. For every gram of carbohydrate consumed, approximately 2-3 grams of water are retained. Therefore, athletes often reduce carbohydrates as a cutting strategy before competition.

Possible warning signs that you have low blood sugar include shaking or sweating (more than usual), or feeling faint. If you're at risk (from doing any of the things mentioned above), it's a good idea to carry a sweet treat with you.

Of all the reasons a person might faint during a deadlift, the most common is improper breathing. The others are much less common or only exacerbate the issue of improper breathing.

However, overall, it's much more common to simply feel dizzy after deadlifting when making these mistakes. Fainting is rare and almost always happens when someone is doing something seriously wrong or has a condition that makes it more likely.

If this is very common for you, then it is recommended to see a doctor and check if there are no secondary causes facilitating the problem.