Meditator or not, everyone who sleeps has to pass through the jhāna highway and charge the jhāna battery

 

Examples of instinctive qigong that everyone does

* every night - you're tired. so you sleep. you wake up, energy replenished body rejuvenated. 

* you have a flu - you're achy, tired, so you sleep.  You're body gets a fever, you sweat, you sleep more than usual, you wake up feeling less ill and eventually recovered after some number of sleeping sessions. 

* the temperature is cold, you're not wearing enough, so your jhāna battery produces body heat by eating into your supply of PIE. This is one reason you should always dress warmly. Especially monks and nuns eating one meal a day. If you have to waste energy to heat the body, then the last 4-8 hours of your fast before you eat is going to be painful. 

* you want to pick up an object with your hand, it requires specific configurations of your fingers to be able to do it without breaking the object, without dropping it, etc. Your mind issues sankhāra intentions of what you want to do, the body does it, and qigong is what's going on between your intention and the body moving. 

Jhāna is just sati and qigong done with singular focus and undistractible lucidity

In the first example, everyone needing to sleep every night, here's an interesting link between the 4 jhānas and sleep. 

Those skilled in at least second jhāna, you should be able infer how the jhāna battery stores PIE (precious internal energy), as well as how big your battery is, how strong the (jhānic) force is and how long it takes to charge, by carefully observing your sleep process every chance you get.

Doing 4 jhānas and sleeping both share part of the same highway. When you go to sleep, sleep doesn't happen until the jhāna battery gets charged first. So you can be totally, physically exhausted, where you normally would just lose consciousness within 20 seconds after lying down, but often you'll find that you'll suddenly be jolted awake with the sukha (physical euphoric sensations linked to endorphins) of the first 3 jhānas. This lasts as long as it takes for your jhāna battery to charge up (for me, between 1min and 20min), and then you immediately fall asleep. 

Unless the jhāna meditator is truly exhausted, then they can just lose consciousness and not notice the jhāna battery getting charged. 

The non-jhāna meditator, must go through the same process when they sleep, except if they get jolted awake, it can lead to insomnia for them because they don't understand what's happening and why they got jolted awake, thinking and worrying about not getting good night's sleep causes them to not fall asleep. Also, whereas the competent jhāna meditator would feel sukha (pleasure) while the battery is charging up, the non jhāna meditator who has depleted too much PIE (precious internal energy) may instead feel neutral, uncomfortable, or even painful vibrations in the body. In other words, even non meditators are doing autonomous jhāna and charging the battery when they sleep, except they may feel neutral or painful sensations instead of pleasure.

If the non-jhāna meditator is someone who keeps 5 precepts, doesn't overindulge in sensual pleasures, is in good health, then they would likely also feel some sukha while falling asleep. Basically doing low quality jhāna meditation without realizing it.

Whether you're competent in jhāna or not, sleep will be painful if...

if you've harmed your jhāna battery and/or drained too much PIE from overindulging in 

(1) sensuality

   - sex or masturbation a huge killer 

   - over eating

   - alcohol, recreational drugs, intoxicants

   - staying up all night playing video games,

   - gambling, socializing, general debauchery

 

(2) any prolonged strong negative emotions (anger, hatred, grief, etc.)

For depleted  PIE (precious internal energy)  and damaged jhāna battery, when you try to sleep, instead of getting sukha (pleasure) while the battery charges, you will instead feel dukkha: uncomfortable or painful vibrations and sensations in the body proportional to how much PIE has been drained, and how much the battery infrastructure has been damaged from strong negative emotions.

If you're a competent jhāna meditator, eat healthy and exercise daily, keep 8 precepts...

Sleep is never a problem. 

If I'm not sleepy I sit and meditate.

If I need to sleep, I fall asleep within a couple of minutes. 

Even if someone were to wake me up every 30 minutes throughout the night, I could fall back asleep easily within a minute and not feel any ill effect the next day.

If some loud noise or continuous disturbance prevents me getting the Buddha recommended daily amount of 4 hours of sleep every night, 

I just power nap throughout the day with 10-30min sessions,  as many times as needed.  

This way I catch up on any sleep deficit that was incurred, without any ill side effects reverberating over the next few days.