Sleep apnea can be related to body weight. But like a lot of relationships, this one is complicated. If you are overweight and have sleep apnea, research shows that losing weight may reduce the severity of your sleep apnea symptoms. But it usually won't eliminate them completely, so you may need to keep using your CPAP machine even after weight loss.
How Obesity Can Lead to Sleep Apnea
People of all shapes and sizes can have sleep apnea. However, your risk increases as your body mass index (BMI) rises. A BMI of 25 to 29 indicates overweight; 30 or above indicates obesity.
What's the link? Obstructive sleep apnea (OSA)—the most common form of sleep apnea—occurs when the upper airway repeatedly becomes blocked during sleep. People with obesity have increased amounts of fatty tissue in their necks. This can impede the flow of air through their upper airways.
How Sleep Apnea Can Affect Body Weight
The relationship between sleep apnea and body weight is a two-way street, however. There's evidence that it may be a bit harder for people with untreated OSA to lose excess pounds. That may partly be due to poor sleep, which leaves them feeling unrested and less inclined to be physically active while awake.
Yet it's still possible for people with both obesity and sleep apnea to slim down. The potential health benefits include improvements in blood pressure, cholesterol, and blood sugar levels.
But Does Losing Weight Actually Improve Sleep Apnea?
No surprise! In people with obesity, losing weight can also lessen the severity of sleep apnea.
One meta-analysis of 80 studies compared the effectiveness of different strategies for managing sleep apnea. Both dietary weight loss and physical activity decreased the apnea-hypopnea index—the number of apnea events occurring per hour of a sleep study. Yet neither could match the overall effectiveness of CPAP therapy.
For example, dietary weight loss led to 12 fewer apnea events per hour, on average. But CPAP use led to an average of 25 fewer apnea events per hour—a substantially larger improvement.
Why Weight Loss Alone Often Isn't Enough
Obesity is a common culprit in sleep apnea, but it's not the only possible cause.
- Certain health conditions, such as hypothyroidism (an underactive thyroid gland), stroke, and heart or kidney failure
- Drinking alcohol or smoking
- Age-related changes in how the brain controls breathing
Aiming for a healthier weight is great for your well-being. But although your sleep apnea might be milder after you lose weight, it may not disappear entirely. As a result, you may need to continue using your CPAP machine. Don't just stop CPAP therapy without discussing it with your health care provider first.