Sleep apnea has been an often-discussed topic in these articles, and I was about to write about the effectiveness of weight loss on improvements in several factors associated with sleep apnea. When looking at the improvement in sleep apnea from weight loss we look at things called endotypes. These are functions which are noted to be abnormal in patients with sleep apnea and seeing how they improve with weight loss tells us how successful this type of treatment has been.
The four major endotypes or factors we evaluate are: how the collapse of the airways is improved, how easy or hard it is to fall or stay asleep, how much improvement there is in the way in which the upper airway muscles respond and lastly something call loop gain. It was this last feature that caught my attention.
Simply put loop gain is a measure of how well we can control our breathing rate. This is not something that is under our control during sleep and depends on the brain and other sensory organs.
Sensing the level of carbon dioxide in our blood is one of the ways we control our breathing. The relation between the sensory organs and brain in regard to our carbon dioxide level defines the “loop.” Patients who have “high loop gain” overshoot their breathing when their levels are high and this results in periods of further apnea.
If you don’t quite understand this concept its ok. I had some trouble as well but I liked the term “loop gain.”
