Why You’re Still Tired With Enough Sleep
The quantity of sleep we get is not the only factor that determines if you wake up still tired; the quality is just as important. There are 5 stages of sleep, and we get low quality sleep when we don’t spend enough time in 2 of those stages. I’m going to focus on the one that’s harder to get and that many of us are lacking in.
*If you’re short on time, skip ahead to the bullet points and summary at the end!*
The Purpose of the 5 Stages
The 5 stages of sleep are awake, light (referred to as N1 and N2), deep (N3) and REM (rapid eye movement). Stage N1 is the transition period from wakefulness to sleep as brainwaves start to slow down. Light sleep continues into stage N2 where heart rate and breathing slow, muscles relax, body temperature drops, and eye movement stops. (1)
After light sleep, the body goes into the deep stage. The body is most at rest during this stage compared to the others, as deep sleep physically restores the body. (2) Not getting enough deep sleep is one of the reasons you wake up feeling still tired. But because the majority of it occurs in the first half of the night, we’re not as likely to be deficient in it as the last stage.
Finally, the last stage in the cycle is REM. It typically begins around 90 minutes after falling asleep, and during it, brain activity is similar to when you’re awake. (3) This activity includes learning and memory consolidation, brain development, motor learning (muscle memory), dreaming, and improving overall mental flexibility. (4) In a healthy adult, 20-25% of total sleep time is in REM. (5)
Let’s dive a little deeper into this vital component of sleep, so you can start waking up feeling refreshed and keep your mental and emotional energy high during the day!
How REM Can Help You Thrive
Ever have those mornings where your brain feels just as fatigued waking up as you did going to sleep? It feels like during the day, all of the files are opened and the papers spread out across the desk. Then when we have a good night’s sleep, it feels like those papers get sorted, and we can wake up with the files closed and neatly stacked on top of each other.
Well, when we don’t get enough REM, it’s like we start the next day with yesterday’s unsorted files and just add more files to it. This can lead to a feeling of overwhelm, mental exhaustion, and brain fog. In the long run, it may even increase your risk of dementia and Parkinson’s. (6)
In addition to mental energy, REM actually improves emotional energy and stability. Since REM is vital for a healthy mood, skimping on it can lead you to waking up emotionally still tired. This can look like a lack of motivation, decreased attention and alertness, irritability, mood swings, and increased negativity. (7) When you’re deprived of REM, you’re more likely to overreact to stressful events, have more fear or anxiousness, and struggle to regulate your emotions and stay in control of them.
Finally, REM is essential for overall good health. Studies show that deficiency is associated with greater risk of death from cardiovascular disease and from all causes in general. A large study of thousands of individuals showed that for every 5% reduction in REM sleep, there was a 13% increase in mortality rate. (8) The risk was most pronounced when REM made up less than 15% of total sleep time. Therefore, the goal should be to aim for the healthy 20-25% range.
How To Get Enough REM
The most important element to getting enough REM sleep, and therefore waking up refreshed instead of still tired, is regulating your circadian rhythm. (9) Your circadian rhythm is the internal clock that regulates many vital functions, including your time spent in the different sleep stages. The more disrupted your rhythm, the harder it’ll be to reach sufficient REM, even if you’re getting 8 hours of sleep.
- Timing: It’s called a rhythm for a reason! If you’re falling asleep and waking up at different times all week long, you’re not in a rhythm. Try to keep bedtime and wake time within a 30min range optimally, but no more than a hour variance.
- Light: It sets the tone for the rhythm. Sunlight and light bulbs tell the brain it’s day time, while darkness or fire light tell the brain it’s night. If you’re being exposed to light outside of the amber or red range, then your brain isn’t telling your body to be ready for sleep. Therefore, even if you do sleep 8 hours, you likely won’t get all of the deep and REM sleep that you need. Indeed, studies show that the blue light spectrum emitted from most of our bulbs and electronics significantly shortens REM sleep. (10)
- Melatonin: This hormone is released as a response to a normal circadian rhythm, which is ruled by the rising and setting of the sun. If we don’t fall asleep before midnight, we suppress melatonin release, and therefore REM can decrease. Some people, such as the elderly or those with PTSD or fibromyalgia, don’t produce enough melatonin in general. A study showed that 3mg melatonin given between 10 and 11pm can significantly increases time spent in REM. (11)
- Alcohol: While I wish I could tell you to drink alcohol more regularly because it’ll help you sleep, it’s actually the opposite that’s true. One of the reasons you wake up still tired after drinking is that it reduces the quality of your sleep. Your body tends to avoid REM while detoxifying from alcohol, so the delay ends up reducing your total time spent in this revitalizing stage. (12) Even though you fall asleep faster and get deep sleep, the lack of REM means you’re still tired in the morning.
Summary: To upgrade your energy levels, make sure you’re getting enough REM sleep by sticking to a bedtime, using amber light at night, adding melatonin if needed, and avoiding alcohol in the evening.
How do you stay on track with your circadian rhythm? What have you noticed makes you wake up feeling more or less refreshed?
1. Brain basics: understanding sleep. 2019. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep
2. Deep sleep maintains learning efficiency of the human brain. 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5458149/
3. Physiology, sleep stages. 2020. https://www.ncbi.nlm.nih.gov/books/NBK526132/
4. The biology of REM sleep. 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5846126/
5. The microstructure of REM sleep: why phasic and tonic? 2020. https://www.sciencedirect.com/science/article/abs/pii/S1087079220300484
6. Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behavior disorder. 2019. https://pubmed.ncbi.nlm.nih.gov/30789229/
7. The role of sleep in emotional brain functioning. 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286245/
8. Association of rapid eye movement sleep with mortality in middle-aged and older adults. 2020. https://pubmed.ncbi.nlm.nih.gov/32628261/
9. Circadian and homeostatic control of rapid eye movement (REM) sleep. 2000. https://www.jneurosci.org/content/20/11/4300
10. Wavelength-dependent effects of evening light exposure on sleep architecture and sleep EEG power density in men. 2006. https://pubmed.ncbi.nlm.nih.gov/16439671/
11. Melatonin in patients with reduced REM sleep duration: two randomized controlled trials. 2004. https://academic.oup.com/jcem/article/89/1/128/2840303
12. Alcohol and sleep I: effects on normal sleep. 2013. https://pubmed.ncbi.nlm.nih.gov/23347102/