Our Breathing is Shallow and Irregular for 1/3 of Our Lives

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

Our somewhat surprising breathing patterns during sleep

We spend 1/3 of our life sleeping. And sleep is arguably one of the most important aspects of good health. Therefore, I expected that during sleep, breathing would be slow, deep, and rhythmic (i.e., “perfect”).

However, a review published in 1984 in Clinical Science showed that breathing rate is actually highly variable during sleep. In fact, breathing rates often increase and become irregular and shallow, especially during rapid eye movement (REM) sleep.

Although breathing rate might increase, the overall breathing volume is reduced, dropping as much as 16% from waking values.

This drop in volume is accompanied by relative hypoxia (low O2) and hypercapnia (high CO2). We discuss improving CO2 tolerance quite often. During sleep, your CO2 tolerance increases by as much as 66%.

What do these findings mean from a practical perspective?

Well, sleep is clearly a time when breathing should reduce and CO2 should increase. Therefore, if you are sleeping with your mouth open, you are likely overbreathing and not reaching the physiological states your body was meant to reach during sleep.

Luckily, this is an easy fix. Simply taping your mouth at night will restore nasal breathing and will provide the first step in reducing breathing volumes to their natural levels during sleep.

If you are not already, give it a shot. This one small change has had the greatest positive impact on my health and energy. It might do the same for you.

In good breath,
Nick