A pharmacist's perspective on health and metabolic disease
At the moment, it seems that every time I turn around, I am finding more associations between insulin and metabolic disease. Now there is a significant link between hyperinsulinaemia and obstructive sleep apnoea (OSA).
People (typically men, but can affect women) who suffer from OSA typically snore very loudly, but may also suffer from insomnia or not have a ‘restful’ sleep. They may wake up during the night breathing hard (shortness of breath) or have periods during the night when they simply stop breathing. Upon awakening, sufferers may have a dry mouth, sore throat, or headache. Due to the poor sleep (quality or quantity) people with OSA may have excessive daytime sleepiness or difficulty concentrating. This sleepiness has led to car accidents when people have fallen asleep at the wheel.
What happens during OSA is that the upper airways collapse and block breathing. When blood oxygen levels drop, it is sensed by the brain, which causes the person to rouse and re-open their airway, then go back to sleep. Often the person does not realise what has happened even though they may be waking (albeit briefly) five to 30 times every hour!
Insulin appears to aggravate OSA though a number of pathways as shown below (reproduced from Eckert & Oliven 2016). Between changes to the nervous system, increasing muscle fatigue, and increased adipose tissue mass, (both in the abdominal cavity and fatty deposits in the tongue or around the neck), insulin mediates changes to breathing.
What makes it worse, is that the breathing changes by themselves can increase cortisol or adrenaline secretion, which creates a feedback cycle that will only worsen the hyperinsulinaemia, making the OSA worse……
Having OSA increases the risk of developing other metabolic diseases, but researchers could not determine if this risk was directly due to the OSA, or if other factors such as obesity confounded the results.
However, now we understand that hyperinsulinaemia can be the common link for all of these disease states, we may be able to prevent OSA as well as many other conditions if we control insulin levels.
Now we just need to persuade the health bodies that carb restriction is a viable option!
Eckert, D. J., & Oliven, A. (2016). When insulin has to work hard to keep the sugar at bay the upper airway collapses away. European Respiratory Journal, 47(6), 1611-1614. doi:10.1183/13993003.00590-2016