Reasons Why You Can Feel Tired After Sleeping

There’s a couple of reasons why you may feel tired even after a good night sleep.

One possibility is that you don’t secrete enough cortisol in the morning to wake you up and clear your head. In a healthy individual, cortisol rises the longer you stay asleep. Such that your level of cortisol is highest compared to at night. Cortisol is a stress hormone that mobilizes energy in the body.

Another possibility is that your quality of sleep is pretty low. There can be a variety of reasons why.

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Sleep Apnea Damages Sleep Quality

sleep apnea diagram image depiction — Credits to Habib M’henni / via Wikimedia Commons

One reason could be that you have sleep apnea, which is when your airway is obstructed while you try to sleep. Such that your body has to keep “waking up” by releasing adrenaline, cortisol, and other “fight or flight” stress hormones.

The body does this because these particular hormones help dilate (open up) the air way from the mouth to the lung, enabling you to breath. Also if you are less deeply asleep, the lungs can contract and expand better to allow for better breathing.

But the result is that for varying periods of time, you stop breathing while you sleep. This is very dangerous and may negatively affect the health of your brain. You need oxygen to live, after all

So because of sleep apnea, you sleep less deeply, and so your sleep is less restorative. Less restorative sleep may be the reason why you still feel tired after sleeping.

Aging Reduces Sleep Quality

But another reason why your quality of sleep is low is because of age. As we age, our quality of sleep diminishes. The older you are, the less you sleep deeply.

This may be due to the pineal gland, located in the brain, no longer secreting melatonin due to age.

position of thalamus in brain — By Life Science Databases. [CC BY-SA 2.1 jp], via Wikimedia Commons

Another reason can be that the thalamus of the brain becomes damaged, affected your sleep. The thalamus is responsible for the regulation of consciousness, sleep, and alertness. So it makes sense that damage to the thalamus can affect your sleep.

An example where damage to the thalamus can affect sleep is a condition called Fatal familial insomnia, which is a prion disease of the brain that slowly kills its victim by slowly removing the person’s ability to sleep. The chronic lack of sleep causes dementia and atrophy of the brain, especially to the thalamus.

Yet another reason why age can affect how rested you feel after sleeping is the amount of growth hormone and other restorative hormones that are secreted while you sleep. If your secretion of growth hormone is inhibited (stopped) while you sleep, then the amount of restoration your body goes through is decreased.

One reason why you wouldn’t secrete enough growth hormone is if you don’t exercise. I personally find that when I exercise, I sleep extremely well. That is because the body is mildly damaged & stressed (in a good way) during exercise. So in response to that, the body secretes more growth hormone to encourage the body to repair itself. This also results in more restful & deep sleep.

Bedtime Affects the Quality of your Sleep

Finally, another reason why you wouldn’t feel sufficiently rested from sleep is from sleeping at the wrong time. By this I mean sleeping late past your typical bed time, or sleeping close to morning.

By sleeping late, you aren’t receiving the biggest boost of melatonin that the human body experiences early in the night. This high level of melatonin is related to the fact that the best quality of sleep is experienced in the beginning of the night.

That’s why you would feel more rested sleeping 4 hours early to bed, vs 4 hours late to bed. The most restorative sleep happens early in the night.

Also when you sleep close to morning, you may “feel” light coming from the window or your environment. The body responds to light, as well as to darkness.

In the dark, you feel sleepy. In the light, you feel awake. That’s because the pineal gland secretes melatonin in the darkness, whereas it stops secretion in (blue) light.

By this fact, using electronics at night may suppress melatonin secretion. Which as 2 effects:

You sleep later, because you don’t feel sleepy
Your quality of sleep is less, because melatonin is suppressed

So, for example, using the phone while falling asleep, or in the middle of the night will negatively affect your quality of sleep. Similarly, watching TV in bed while falling in sleep negatively impacts your quality of sleep.

To conclude, you may find that your aren’t feeling rested from your sleep because of sleep apnea, age, damage to the thalamus of the brain, sleeping at the wrong time, and using electronics late into the night.