Adults yawn about nine times a day on average, though some people yawn up to 20 times without anything being wrong. Frequent yawning becomes a potential concern when it exceeds roughly three yawns per 15 minutes, multiple times throughout the day. Some people with truly excessive yawning report 100 or more episodes daily. The causes range from simple sleep deprivation to medication side effects to, in rare cases, neurological conditions.
What Yawning Actually Does
For decades, people assumed yawning pulled more oxygen into the lungs. That theory has largely fallen out of favor. The leading explanation now is that yawning cools the brain. When you yawn, the deep inhalation of air creates a heat exchange that lowers brain temperature slightly. Your brain runs best within a narrow temperature range, and yawning appears to be one of the body’s built-in cooling mechanisms.
This helps explain why you yawn more when you’re tired. Sleep deprivation raises brain temperature, and a fatigued brain generates more heat with less efficient cooling. The same logic applies to boredom: when your attention drifts and mental activity shifts, your brain’s thermal regulation can trigger a yawn to reset.
Sleep Problems and Low Oxygen
The most common medical reason for frequent yawning is simply not getting enough quality sleep. But the “why” behind poor sleep matters. Obstructive sleep apnea, where your airway repeatedly collapses during the night, fragments sleep and drops your blood oxygen levels. Research has found a direct link between those oxygen dips and yawning episodes. In one documented case, a patient yawned five times per hour during sleep. When treated with a pressurized air mask (PAP therapy), yawning dropped to 1.3 episodes per hour, and the patient’s minimum oxygen saturation improved from 76% to 86%.
That resolution of yawning once oxygen levels improved strongly suggests that low oxygen drives the behavior. If you’re yawning excessively during the day and also snore, wake up with headaches, or feel unrested despite a full night in bed, fragmented sleep from apnea could be the underlying cause.
Medications That Trigger Yawning
A class of antidepressants called SSRIs (selective serotonin reuptake inhibitors) is one of the most well-documented medication-related causes of excessive yawning. These drugs increase serotonin activity in the brain, and yawning severity tends to rise after starting them. A 2025 prospective study confirmed that yawning increases with SSRI use and correlates with the severity of depression itself, making it hard to untangle whether the yawning comes from the medication, the condition, or both.
If you started yawning noticeably more after beginning an antidepressant or changing your dose, the medication is a likely contributor. Other drugs that affect brain chemistry, including some anti-seizure and anti-nausea medications, can have the same effect.
The Vagus Nerve Connection
Your vagus nerve runs from your brainstem down through your chest and abdomen, controlling heart rate and blood pressure without any conscious effort on your part. When this nerve becomes overactive, it can cause your heart rate and blood pressure to drop too quickly, a condition called vasovagal syncope. Yawning is one of the recognized warning signs, alongside sudden fatigue, lightheadedness, nausea, sweating, and tunnel vision.
This type of yawning feels different from ordinary tiredness. It often comes in clusters and may be accompanied by that warm, dizzy feeling that precedes fainting. If your excessive yawning pairs with any of those symptoms, particularly near-fainting episodes, it points toward a cardiovascular or autonomic nervous system issue rather than simple fatigue.
Neurological Conditions
Excessive yawning can be a symptom of several neurological conditions, though these are far less common causes. People with multiple sclerosis yawn significantly more than healthy controls, according to research using continuous monitoring. Interestingly, the increased yawning in MS patients didn’t consistently correspond to damage in the brainstem (the area traditionally thought to control yawning), suggesting the mechanism is more complex than a single damaged region.
Pathological yawning, defined as yawning at a rate well above normal without any obvious trigger like boredom or tiredness, can also appear as part of epileptic seizures, before migraines, after strokes (particularly in the upper brainstem), and with Parkinson’s disease. Increased pressure inside the skull from infections or brain tumors is another rare but serious cause. When yawning is driven by a neurological condition, it typically appears alongside other symptoms like weakness, vision changes, or coordination problems.
Fatigue From Nutritional Deficiencies
There’s no direct scientific evidence that a vitamin deficiency causes excessive yawning on its own. However, certain deficiencies cause significant fatigue, and fatigue reliably increases yawning. Iron deficiency and B12 deficiency both lead to forms of anemia where your blood carries less oxygen or your red blood cells don’t function efficiently. The resulting exhaustion and possible oxygen reduction can push yawning frequency well above normal. If your yawning comes with persistent tiredness, pale skin, or feeling winded easily, a simple blood test can check for these deficiencies.
Why Yawning Is Contagious
If you’re yawning a lot simply because the people around you are yawning, that’s a separate phenomenon with its own brain circuitry. Contagious yawning activates a region in the front of the brain associated with empathy and emotional processing. Brain imaging studies show that the urge to yawn when you see someone else yawn lights up areas involved in understanding other people’s mental states, not the areas responsible for copying movements.
This is why contagious yawning appears to be unique to humans and possibly some primates. People with damage to the front of the brain, or conditions that affect empathy processing, tend to be less susceptible to catching yawns. If you find yourself yawning after watching others yawn (or even reading about yawning right now), it reflects social brain wiring, not a medical problem.
Sorting Out the Cause
The most practical way to figure out why you’re yawning excessively is to work backward through the most common explanations first. Poor sleep is by far the leading cause. If you’re sleeping fewer than seven hours, waking frequently, or feeling unrefreshed in the morning, addressing sleep quality will likely reduce your yawning. Next, check your medication list, particularly SSRIs and other drugs that affect brain chemistry. After that, consider whether the yawning comes with other symptoms like dizziness, faintness, or neurological changes that suggest something beyond simple fatigue.
Occasional bursts of frequent yawning during a boring meeting or after a rough night are completely normal physiology. The pattern that warrants attention is persistent, frequent yawning throughout the day, especially when it happens regardless of how well you’ve slept and whether or not you’re bored.