When no amount of sleep feels refreshing and your days are heavy

You clearly slept, but you don't feel refreshed. From the morning your body is heavy, and all day your head isn't clear.

These people don't have much trouble falling asleep, so it's even awkward to call it insomnia. Even when they get tested, they're told there's no particular disease. Then it tends to get wrapped up with "it's the age where being tired is only natural."

In these cases, I don't just look at the length of time asleep. I first look at whether sleep is properly doing its job of restoring the body.

Why sleep doesn't refresh you — sleep is not time, it's restoration

Sleep is not merely time spent with your eyes closed. While you sleep, the body must switch off the sympathetic nervous system that was on during the day and hand over to the parasympathetic nervous system in charge of restoration. At this point the heart slows, the muscles relax, and the brain washes out the day's residue. But if the body can't let go of tension even while lying in bed, you sleep, yet you don't descend deeply into this restorative stage. So you filled the time but don't feel refreshed. It amounts to having slept a long, shallow sleep.

There are things that block this transition. Tension and thoughts that continue right up until you sleep, shallow and frequent breathing, late-night light and screens, caffeine and alcohol, and cases where the day's overwork carries over into the night. It's a state where the switch that moves the body from day mode to night mode has grown stiff.

For sleep to do its restorative work, the autonomic nervous system has to shift toward the parasympathetic side. When that transition is disturbed, the quality of sleep drops.

I see this fatigue as arising not from "not enough sleep" but from sleep failing to connect to restoration. So even if you forcibly lengthen your sleeping time, the refreshed feeling doesn't come back easily. The direction is to smooth the switch that moves you from day to night.

I look first at the crossing into sleep

I look first at the process of transitioning into sleep, rather than the time asleep.

I check whether the body lets go of tension until you sleep, whether the breathing settles, and whether light, screens, and caffeine keep the switch turned on. When I lay these conditions to rest one by one, sleep descends more deeply into the restorative stage. Herbal medicine I use on that stiffened switch. When it becomes easier for the body to come out of tension at night, the same hours of sleep make a different morning.

Cases where you should go to a hospital first

But daytime fatigue has causes that must be confirmed. If you're told you snore loudly and stop breathing while asleep, or you have a headache even after sleeping and are unbearably sleepy during the day, you should first check for sleep apnea. Hypothyroidism, anemia, and depression also produce a heavy fatigue that persists after sleep. If the fatigue keeps worsening or comes with a change in weight, testing is needed.

Time lying down is not time recovered

Sleep is not a thing that ends by filling the hours. The time spent lying down and the time spent restoring are different. If eight hours still leave you unrefreshed, it is not that the hours were short but that the work to be done in those hours went unfinished. It is not a matter of will. What I look at is what got in the way of that work.

Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)