Sleep Apnea and Obesity: The Chicken or the Egg
My patients suffering with obesity are always surprised and worried about having sleep apnea.
I let them know that sleep apnea occurs in around 25% of people with mild obesity and more than 50% in those with severe obesity. The discussion quickly progresses to the dangers associated with this diagnosis, including hypertension, metabolic syndrome with insulin resistance, heart failure and increased risk of death.
They always ask me about the cause of sleep apnea and what can be done about it.
Sleep apnea is a condition where the airway partially collapses leading to episodes of stopping breathing or very ineffective breathing called hypopnea. While sleep specialists look at numerous variables, the main measurement is the Apnea-hypopnea index or AHI. When the AHI is greater than 15, the person is diagnosed with moderate or severe sleep apnea, which can lead to many life shortening diseases.
It's easy enough to explain that progressing into severe obesity leads to worsening sleep apnea. The other perspective is whether having sleep apnea causes weight gain. A practical explanation implies that a person who has very poor quality sleep and is tired all the time will not be able to get adequate physical activity and subsequently gains weight.
What's fascinating is whether hormones that control hunger and fullness can play a role in contributing to weight gain in people with sleep apnea. I'm referring to two specific hormones: ghrelin and leptin. Ghrelin is made predominantly in the stomach and is considered a hunger hormone. When a person hasn't eaten in a while, ghrelin levels increase causing the individual to feel hungry and proceed to eat the next meal.
Counterbalancing ghrelin is leptin, released by fat cells. When a person gains weight and the fat cells sense too much energy deposition, leptin is released causing neurotransmitters to indicate that it's time to decrease food intake. In theory, once leptin is elevated, the person feels less hungry, eats smaller portions and loses fat deposits.
Unlike obesity contributing to worsening sleep apnea, the reverse is not so clear. Numerous studies have looked at the correlation of having sleep apnea with subsequent changes in ghrelin and leptin levels. While it's logical to conclude that sleep apnea causes the hunger hormone to increase while the fullness hormone decreases, ultimately leading to weight gain, the human body and brain are complex. Simple answers hardly explain the processes occurring.
Given the current knowledge base, it's safe to say that the causation of obesity towards having sleep apnea is very well documented. The reverse is not so simple, implying that having sleep apnea doesn't necessarily lead to weight gain.
The best practical advice is to discuss your sleep patterns with your medical doctor and ask if you should consult with a sleep specialist. If you're found to have sleep apnea, there are many treatment options available, but most don't treat the underlying cause, namely obesity. The two most powerful treatment options include bariatric surgery and the modern injectable medication Zepbound. Ideally your sleep specialist should collaborate with your weight loss specialist. Now that you know the story, consider utilizing some of the many treatment options, with weight loss being the best option for a possible cure.
Stay Healthy, Stay Strong
Dr. Leon Katz
Sources:
The Impact of Sleep-Disordered Breathing on Ghrelin,
Obestatin, and Leptin Profiles in Patients with Obesity
or Overweight. Piotr Parda, MD et al. J. Clin. Med. 2022, 11, 2032.
https://www.mdpi.com/2077-0383/11/7/2032
Increases in leptin levels, sympathetic drive, and weight gain in obstructive sleep apnea. Bradley G. Phillips MD et al. Am J Physiol Heart Circ Physiol
279: H234–H237, 2000.
https://journals.physiology.org/doi/pdf/10.1152/ajpheart.2000.279.1.h234
Obstructive sleep apnoea in obesity: A review. Jian E. Tai et al. Clinical Obesity. 2024;14:e12651. https://onlinelibrary.wiley.com/doi/pdf/10.1111/cob.12651
This article is strictly for educational purposes. Please consult with your healthcare professional regarding any questions or treatment options.
