Midday Nap: Causes And Concerns

[jyb]

What do you think of midday or afternoon nap feeling? I'm uncertain about what really causes it. I think that heavy meals no doubt can contribute to somnolence. But I don't think it's the whole story. In my experience since I was a kid, and I've been on many different diets and lifestyles, it can happen even if I didn't eat much, and doesn't seem related to how much fat or carb I was eating earlier in the day.

Ray writes that serotonin causes torpor from serotonin. But is feeling like having a nap caused by serotonin and therefore harmful & avoidable? I feel the answer is not obvious. If I feel relaxed and my body temps is high, yet would very much like to lay down and nap, is this really serotonin? I think at the same time, it is suspicious to be needing a nap if one has slept well the previous nights, I feel like it should be avoidable.

Wikipedia gives a few possible explanations. I selected two. I'm wondering if it could be some proteins promoting insulin and therefore tryptophan uptake. Dairy proteins are said to stimulate insulin a lot, so I'm sure my insulin is being stimulated plenty. I guess I could always test the insulin hypothesis by eating a lot BCAA or glycine in the morning to prevent tryptophan uptake and seeing whether that has any effect on afternoon naps.

https://en.wikipedia.org/wiki/Postprandial_somnolence

Parasympathetic activation[edit]
In response to the arrival of food in the stomach and small intestine, the activity of the parasympathetic nervous system increases and the activity of the sympathetic nervous system decreases.[1][2] This shift in the balance of autonomic tone towards the parasympathetic system results in a subjective state of low energy and a desire to be at rest, the opposite of the fight-or-flight state induced by high sympathetic tone. The larger the meal, the greater the shift in autonomic tone towards the parasympathetic system, regardless of the composition of the meal.[citation needed]

Insulin, large neutral amino acids, and tryptophan[edit]
When foods with a high glycemic index are consumed, the carbohydrate in the food is digested more easily than low glycemic index foods. Hence, more glucose is available for absorption. It should not be misunderstood that glucose is absorbed more rapidly. Because once formed glucose is absorbed at the same rate. It is only available in higher amounts due to the easiness of digestion of high glycemic index foods. In individuals with normal carbohydrate metabolism, insulin levels rise concordantly to drive glucose into the body's tissues and maintain blood glucose levels in the normal range.[3] Insulin stimulates the uptake of valine, leucine, and isoleucine into skeletal muscle, but not uptake of tryptophan. This lowers the ratio of these branched-chain amino acids in the bloodstream relative to tryptophan[4] (an aromatic amino acid), making tryptophan preferentially available to the large neutral amino acid transporter at the blood–brain barrier.[5] Uptake of tryptophan by the brain thus increases. In the brain, tryptophan is converted to serotonin,[6] which is then converted to melatonin. Increased brain serotonin and melatonin levels result in sleepiness.[7] [8]

 

[cantstoppeating]

...

I guess I could always test the insulin hypothesis by eating a lot BCAA or glycine in the morning to prevent tryptophan uptake and seeing whether that has any effect on afternoon naps.

Sounds like plan, look forward to your results.

 

[mt_dreams]

Are we talking midday naps or midday tiredness?
If you've taken enough midday naps throughout your life, there will a memory of this, which will make it easier to take one. Whenever I've exerted myself mentally or physically (and know I will have to do more later in the day), I like to get in a nap refresh if I can. I'm not really tired per say, rather I know the refresh will make later day exertion a lot easier than without a nap. If you're actually feeling tired, then I think it's something to play around with via testing.

I don't think a lion shames itself when it lies down for some midday shuteye. If there is nothing that needs your immediate attention or that you're putting off via procrastination, naps are to be enjoyed. If the nap is holding you back from doing something you consider important, then that might be a problem sign.

 

[jyb]

I find it hard to make the difference between tiredness and nap when the nap feeling hits you, if you see what I mean. When I think of real tiredness its more for a large part of the day and has a clear cause, like after a short night sleep for example. With a nap feeling its localised in time, typically afternoon, and occurs unexpectedly. But if it occurs, I really want to lay down and take a break. At that point, its only a small difference between relaxedness and tiredness. Obviously I'd rather not have that happen when at work - the brain is less focussed and distracted by the though of having a nice nap. Sometimes this resolves quickly without doing anything, sometimes its takes a little longer.

I can't exclude this nap feeling is just a form of tiredness and poor health. However I find it surprising that after fixing so many severe issues, including curing my lifelong sleep problems, there is still no effect on the nap experience.

 

[mt_dreams]

In the animal kingdom a midday nap is the result of either an excessive amount of energy output in the first half of the day, or b/c they're relaxed, and enjoy the experience. So you can be quite healthy, and still desire a midday nap. It would make sense that the most draining part of the day would be the best time to take a nap, not to mention that by this time your body has finally normalized from it's daily morning stressors.

I can attest to the feeling of tiredness midday in the past when I was routinely takes naps most days. I figured this was more of an pre-nap effect than a true measure of energy, as days when I was busy & couldn't take a nap, I had no problems making it though the day. The midday tiredness effect was comparable to the effect cooling my body has, as it gets me in the mood for slumber.

 

[Wilfrid]

When you feel relaxed and your body temperature is high, the need of taking a nap could be a sign of good thyroid function rather than just a serotonin related problem.
Ray has said something about it: "....some people want to have a nap in the afternoon when their thyroid is good." ( quote from Ray Peat FAQ )
Not sure if it's applying to your situation but when your overall metabolic indicators are good, the connection between " good thyroid function = afternoon nap need " seems very likely to be one good reason, at least for some individuals.

 

[tara]

I'm envious. :)
Wish I was good at taking a nap when I need one.
I read about a study many years ago that showed university students who habitually napped during the day did better in the afternoons. No idea if it was a well designed study.