If you’re a morning exerciser who’s no stranger to being up before the sun, yawning before or early into a workout isn’t strange. But is it normal to yawn while exercising if you’ve had a full night’s sleep and feel energized? If you’ve ever found yourself yawning during a workout in what feels more like an unconscious behavior than a sleepy one, you might be wondering what this means.

The short answer is that science isn’t clear on why you yawn during a workout (it’s an involuntary reflex, after all), and maybe it’s just one of those things exercise can cause your body to do, but there are a few theories. Learn those, plus what to do if it’s happening to you, below.

Potential reasons for yawning during a workout

From oxygen demand to brain thermoregulation, there are several theories as to why you might be yawning during exercise—some more plausible than others.

Yawning and oxygen consumption

“It’s a common misconception that yawning is about getting more oxygen,” explains Florida-based exercise physiologist Sharon Gam, PhD, CSCS. The long-standing theory has been debunked for decades thanks to a series of research in the 1980s¹.

“You’re able to maintain appropriate oxygen concentrations despite intense exercise,” says Heather Milton, MS, CSCS, exercise physiologist at NYU Langone’s Sports Performance Center.

In healthy people, respiratory reserve, or the amount of air that stays in your lungs even at max exhalation, is roughly 30 percent, she explains. Therefore, “yawning is not done to increase oxygen delivery to the bloodstream as [respiratory reserve] is never low enough to need a stimulus other than inhaling more rapidly and deeply as we do with exercise,” she says.

Yawning and fatigue

Going back to basics, yawning (during a workout or otherwise) may simply be a form of arousal. If you’re trying to finish a work project on little sleep, are bored stiff listening to a presentation, or are going into an evening workout after a long day (despite how well you slept the night before), it’s thought that yawning will make you more alert, says Milton.

Yawning induces physiological effects that would validate this, including increasing your heart rate². Not to mention, yawning “stimulates a series of events including muscular contraction, diagrammatic contraction, and deep inhalation,” says Milton.

It’s easy to see how all of this could contribute to fighting fatigue, or even trying to rev you up if you’re bored with your workout. Think of it as a primer for your mind and body to start firing ahead of a workout to give you better focus and improve performance.

Yawning and thermoregulation

Currently, one of the most widely accepted reasons for yawning during a workout has to do with managing brain temperature³, says Milton. “Brain cooling,”⁴ or the phenomenon of declining brain temperature post-yawn, has been reported in rodent and other animal studies, but it’s worth noting that human research is limited.

Brain temperature is determined by arterial blood (or oxygenated blood carried by the arteries) temperature, the rate of blood flow, and metabolic heat production (the heat generated by everyday bodily function), explains Milton. Exercise increases all three of these things, therefore you could reason that “brain temperature could rise during exercise, and yawning would allow for warmer blood to exit the skull,” she says.

What’s more, facial muscle contraction, deeply inhaling cool air, and even watery eyes that can happen during a yawn may each play a role in the brain cooling that occurs post-yawn, according to one study⁵.

When yawning during workouts is cause for concern

“Yawning doesn’t seem to be correlated to a lack of safety or signify a big health concern,” says Chelsea Long, CSCS, TPI, an exercise physiologist at the Hospital for Special Surgery in New York City. “But taking note of how you’re feeling and what your breathing mechanics are could help stimulate a better brain cooling mechanism.”

If yawning seems to be a recurring thing and bothers you, she says, utilizing a forehead ice pack, wiping your sweat with towels, drinking cooler water, and being well-hydrated for a workout could help. Dr. Gam adds that if you experience excessive yawning, you should get it checked by a doctor just to be sure nothing else is going on you need to know about.

So, what should you do if you’re yawning during workouts?

Regardless of why it happens, here are some factors to keep in mind, plus a few strategies to stop yawning while working out and enhance exercise performance.

Keep track of the habit

Before jumping to conclusions about your health or your fitness, take stock of when you notice the yawning occurring, says Cristina Chan, CPT, instructor at F45, and the brand’s face of recovery. Do you notice yourself yawning only during morning workouts or high-intensity exercise? What about the types of workouts—are you yawning more so during aerobic activity than strength training?

If you’re into data, you could consider using a heart rate monitor to see where your BPM lands during bouts of yawning, says Chan. Just remember, there’s no indication that yawning during workouts has anything to do with your cardiovascular health, so use these metrics to gather info rather than to self-diagnose.

Prioritize quality sleep

Your habit of yawning during workouts might be easily explained if you take a closer look at your sleep. “The quality and quantity of sleep affects everything from physical and mental performance to general health and well-being,” including recovery and muscle regeneration, says Chan.

That means it’s not just about time spent in bed, but the quality of the rest you’re getting. Specifically, in the “deep sleep” phase, your body releases growth hormones, which start repairing the muscle fiber damage that occurs during workouts, she says. “This repair process is what actually leads to muscle growth and the way physical fitness improves over time,” she adds.

In the short term, lack of sleep can impact your fitness performance by reducing hand-eye coordination, reaction time, mood and motivation, and more, adds Chan. Over time, the effects of sleep deprivation can contribute to overtraining.

Curb yawning in the moment

When all else fails and you still find yourself mid-yawn and with low or no energy during a workout, there are a few tricks of the trade to regain focus. Try slowing down your pace so that you’re better able to time your breath to your movement, says Chan. (Check out these three pre-workout breathing exercises for inspiration.)

You could also try scheduling a workout with a friend or a coach, or consider signing up for a class if that helps boost your motivation and alertness, she says (but know, yawning tends to be contagious, so if others around you are yawning, you likely will be, too).

If you’re bored with the same old at-home workouts, head outside to switch it up and get a boost from the fresh air. Oh, and a good workout playlist never hurt anything—pump up the tunes to take your mind off the yawning, if need be.

Know your stopping point

Listening to your body will ensure you know when to push through workout fatigue or hit pause. Yawning or not, pay attention to the signs that your body is telling you it needs rest, says Chan.

For example, if you’ve been training hard for multiple days in a row and can’t stay alert, it may be best to revisit your workout the next day, she says. (And it’s good to know when you need a workout or sleep to boost energy.) However, if you are feeling well-rested physically, but are just feeling unmotivated, that’s cause for digging deep to harness the motivation to keep at it.