Updated: Apr 21, 2022
Although sleep is thought to be inversely proportional to age, meaning that as we age, we need less sleep, our current understanding of sleep is that it should be determined based on the needs of the individual. The best metric to decide the amount of sleep that is sufficient for an individual is to determine whether they feel rested upon waking up, feel awake and alert most of the day, and can complete their daily tasks effectively. Some people need more than nine hours of sleep, while others need less. For instance, a lab at the university of California studied a woman that needed four hours of sleep a night to wake up feeling well-rested. They found a gene mutation on the woman’s DEC2, which ran in her family, that allowed people to thrive on less sleep. [1,5,8]
Why do we need sleep, and what does it do for us?
There is a condition, known as fatal familial insomnia, which is a very rare neural degenerative disorder that eventually leads to the inability to sleep. Not being able to sleep for an extended period causes a disruption in the body’s most basic involuntary abilities, like sweating, body temperature regulation, and breathing. This disorder leads to death within a few weeks to months after onset. There is no definitive answer in the current literature for what sleep does to us, but there is a myriad of postulated theories. One theory proposes the brain is washed over with a neural solution, only in our sleep, that leads to synaptic pruning, which allows for our brain to get rid of excess waste and perform more optimally the next day. [2,6]
Can you recover from lack of sleep?
35% of adults and around 70% of teenagers report consistent insufficient sleep. Luckily, when people experience insufficient sleep, they undergo REM rebound the next time slumbering. This allows people to experience a deeper sleep after a few restless nights. REM rebound is so powerful, that in 1965, when a boy, Rodney Gardner, decided to stay awake for eleven days straight for a school science fair project, he recovered fully, physically, and mentally, within a matter of a few nights sleep. [3,7]
How do you improve your sleep?
Proper “sleep hygiene” is important for quality sleep, maintaining a positive sleep space, and following a consistent nighttime routine. Effective sleep spaces are devoid of electronic devices and distractions. Theses spaces should be associated with sleep, and time spent in the bed should only be for sleep. Optimal sleeping conditions include a quiet environment, or one with white noise, that is around 65 degrees Fahrenheit and pitch black. It’s also important to have the same pre-sleep ritual practices every night, including going to bed at the same time. 
Long story short, if you feel well-rested after waking up and can get through your day feeling energized, you’re probably getting enough sleep, but if you feel fatigued throughout the day, try adding a couple hours to your sleep schedule.
1. Chaput, J., et al. (2018). Sleeping hours: what is the ideal number and how does age impact this? NCBI. 10, 421-430. doi: 10.2147/NSS.S163071
2. Cohut, M. (2019). How waste gets ‘washed out’ of our brains during sleep. Medical News Today. Retrieved from https://www.medicalnewstoday.com/articles/326896
3. Feriante, J., et al. (2021). REM rebound effect. NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK560713/
4. Pacheco, D. (2020). The bedroom environment. Sleep Foundation. Retrieved from https://www.sleepfoundation.org/bedroom-environment
5. Perry, G., et al. (2013). Raising awareness of sleep as a healthy behavior. NCBI. 10(133). doi: 10.5888/pcd10.130081
6. Fatal familial insomnia. (2018). NORD. Retrieved from https://rarediseases.org/rare-diseases/fatal-familial-insomnia/
7. How long can humans stay awake? (2002). Scientific American. Retrieved from https://www.scientificamerican.com/article/how-long-can-humans-stay/
8. Thomson, H. (2015). Is it true that some people need only a few hours of sleep? Future. Retrieved from https://www.bbc.com/future/article/20150706-the-woman-who-barely-sleeps
Author: Katrina Peavy
Editor: Lauryn Agron
Health scientist: Carmen Havyarimana