Sleep apnea and insomnia are not the same condition. They have different causes, different symptoms, and require different treatments. Sleep apnea is a breathing disorder where your airway repeatedly closes during sleep, while insomnia is a condition where you struggle to fall asleep, stay asleep, or both. That said, the two overlap more often than most people realize, and having one can make the other worse.
What Happens in Each Condition
Sleep apnea is a physical, mechanical problem. During sleep, the muscles in your throat relax too much and partially or fully block your airway. This causes you to stop breathing briefly, sometimes dozens of times per hour. Each pause drops your blood oxygen levels and triggers a jolt from your nervous system to restart breathing. You may never fully wake up during these episodes, but they fragment your sleep and prevent you from reaching the deep, restorative stages.
Insomnia is driven by a different mechanism entirely. Rather than a blocked airway, insomnia involves a state of hyperarousal, meaning your brain stays too “switched on” at night. This shows up as racing thoughts, elevated body temperature, increased muscle tension, and a revved-up stress response. The result is difficulty falling asleep, waking up repeatedly, or waking too early and being unable to get back to sleep. When these problems persist for at least three months and affect your daytime functioning, it qualifies as chronic insomnia.
How Symptoms Differ
The hallmark signs of sleep apnea are things you often can’t observe yourself: loud snoring, gasping or choking during sleep, and pauses in breathing that a bed partner might notice. During the day, sleep apnea typically causes heavy sleepiness, the kind where you could fall asleep in a waiting room or during a meeting.
Insomnia looks different at night. You’re lying awake, aware that you can’t sleep, often anxious about it. You might watch the clock, feel frustrated, or find your mind cycling through worries. Daytime symptoms lean more toward fatigue, irritability, and difficulty concentrating rather than the overwhelming drowsiness that characterizes sleep apnea. The distinction matters: someone with sleep apnea often falls asleep too easily during the day, while someone with insomnia often can’t sleep even when they desperately want to.
Different Risk Factors
The biggest risk factor for sleep apnea is excess body weight. A BMI of 25 or higher more than doubles the odds of developing obstructive sleep apnea, because fat deposits around the throat and chest compress the airway. Age, male sex, and a naturally narrow airway also increase risk.
Insomnia has a weaker link to body weight (a BMI over 25 raises the odds by about 17%) and a stronger connection to psychological and behavioral factors. Stress, anxiety, depression, irregular sleep schedules, caffeine and alcohol use, and physical inactivity all contribute. Women are more likely than men to develop insomnia, and the risk increases with age for both sexes.
How Common Each Condition Is
Both are remarkably prevalent. Sleep apnea affects roughly 10% to 20% of middle-aged and older adults, though many cases go undiagnosed because the person sleeping doesn’t realize their breathing is interrupted. Global estimates put the prevalence of insomnia at about 16% of adults, totaling over 850 million people worldwide. Nearly half of those, around 415 million, have severe insomnia.
Having Both at the Same Time
Here’s what surprises many people: sleep apnea and insomnia frequently occur together. This combination is called COMISA (comorbid insomnia and sleep apnea), and it’s the most common pairing of sleep disorders. Roughly 35% to 43% of people with insomnia also meet the criteria for sleep apnea, and about 38% to 58% of people with sleep apnea report significant insomnia symptoms.
The two conditions feed each other in a cycle. Sleep apnea causes repeated awakenings and surges of stress hormones throughout the night, which can train your brain into a pattern of nighttime alertness that eventually becomes insomnia. Going the other direction, chronic sleep loss from insomnia may make the airway more prone to collapse and lower the threshold at which breathing disruptions wake you up, potentially worsening apnea.
This overlap is one reason the conditions get confused. If you’re waking up multiple times a night and feeling exhausted during the day, either condition (or both) could be responsible.
How Each Is Diagnosed
The diagnostic process is completely different for each condition, which reflects how different they really are. Sleep apnea requires a physical test: either an overnight sleep study in a lab or a home sleep test that monitors your breathing, oxygen levels, and airflow while you sleep. The goal is to count how many times per hour your breathing stops or slows down.
Insomnia is diagnosed through clinical interviews, sleep diaries, and questionnaires. There’s no machine that can detect it. Instead, a clinician will ask about your sleep patterns, how long it takes you to fall asleep, how often you wake up, what your bedtime routine looks like, and whether you experience racing thoughts or anxiety around sleep. You may be asked to keep a detailed sleep log for one to two weeks.
Treatment Looks Very Different
Sleep apnea is treated primarily by keeping the airway open during sleep. The most common approach is a CPAP machine, which delivers a steady stream of air pressure through a mask to prevent your throat from collapsing. Oral appliances that reposition the jaw are another option, and weight loss can significantly reduce the severity of apnea in people who are overweight.
Insomnia treatment centers on retraining your brain’s relationship with sleep. The gold-standard approach is cognitive behavioral therapy for insomnia (CBT-I), a structured program that addresses the thoughts and behaviors keeping you awake. It typically involves techniques like restricting the time you spend in bed to match the time you actually sleep, eliminating stimulating activities in the bedroom, and breaking the habit of lying awake worrying about not sleeping. Sleeping pills are sometimes used short-term, but CBT-I produces longer-lasting results without medication.
When both conditions are present, treating one without addressing the other often leads to poor results. People with untreated insomnia use their CPAP machines significantly less. One study of veterans with sleep apnea found that those with comorbid insomnia averaged only 2.8 hours of CPAP use per night, compared to about 4 hours for those without insomnia. They were also far less likely to use the machine for the minimum 4 hours considered effective (32% of nights vs. 51%). Treating insomnia first, or at the same time as starting CPAP, can remove a major barrier to successful apnea management.
Long-Term Health Risks
Left untreated, both conditions carry serious health consequences, though the specific risks differ. Sleep apnea’s repeated oxygen drops and stress hormone surges damage blood vessels over time, increasing the risk of high blood pressure, heart disease, atrial fibrillation, heart failure, and stroke. It also contributes to cognitive decline and depression.
Chronic insomnia raises cardiovascular risk as well, including hypertension and coronary heart disease, but its most pronounced effects tend to be on mental health. Persistent insomnia is strongly linked to depression, anxiety, and impaired memory and concentration. When both conditions are present, the health consequences compound: people with COMISA face greater cardiovascular risk and worse quality of life than those with either condition alone.