Two weeks ago, we discussed some surprising aspects of breathing during sleep.
Quick recap:
Breathing volume is significantly reduced (by 8-16%)
O2 drops and CO2 increases significantly
Breathing rate remains the same, or even increases
I often work backwards, reading one paper, then getting super excited and reading the papers it referenced. The study I’m sharing this is part of my trip down the rabbit hole of breathing during sleep.
Respiration During Sleep in Normal Man
(Click Here to Read the Full Summary)
Healthy participants were studied during sleep between the hours of 10 PM and 7 AM. None of the subjects reported sleep problems or sleep-disordered breathing (not that they would know, I guess).
They found that during non-REM sleep, breathing volume reduced between 6% and 8% from awake values. During REM sleep, breathing volume decreased by as much as 16%. Interestingly, most of these subjects had a faster breathing rate during sleep. This suggests that their breathing was shallower and lighter during sleep than while awake.
Their breathing patterns were also irregular, especially during REM sleep. (Some participants had somewhat regular breathing during non-REM sleep, but they all had unstable breathing during REM). This reduced and irregular breathing led to an estimated 39% decrease in gas exchange in the lungs, which then led to relative hypoxia (low O2) and hypercapnia (high CO2).
And the most interesting part? These findings are considered normal. These somewhat counterintuitive breathing patterns are what our bodies are meant to do during sleep.
Personally, I find it fascinating that during our body’s most restorative process (and when we have no control), our breathing is significantly reduced. If we naturally breathe less and increase CO2 during sleep, there is clearly something to it.
I’m not quite sure what to make of our shallow breathing during sleep. It might be that, because we’re lying down, we don’t need to bring air as deep into our lungs to match blood flow. In any case, it appears to be related to breathing less.
If we breathe less during sleep, and sleep is so important for health, maybe we should try it during the day sometimes too?
In good breath,
Nick