Below write-up was lifted from reddit.
Each person's brain has a set number of hours of sleep that is required for proper functioning. Don't listen to your parents, co workers or boss telling you that a human only needs 4-6 hours of sleep. Less sleep over long period can lead to poor memory, mental health issues and even Alzheimer's
For example, I require 7 hours of sleep. On days where I sleep less. I'm annoyed, my memory and concentration ability is affected. I feel mentally sick through the day. Once I went a few days like this and then one day I had a good sleep. I realised how important sleep was. Your brain functions so much better. Everything is more clear.
Just pay attention to how you perform on less sleep to understand this.
There are many studies showing association of poor sleep with dementia and Alzheimer's.
There are studies that showing association of poor sleep with high blood pressure and cardiovascular diseases.
Edit 1: Many had asked about source for my claims
https://www.nih.gov/news-events/nih-research-matters/sleep-deprivation-increases-alzheimers-protein
https://www.nih.gov/news-events/nih-research-matters/lack-sleep-middle-age-may-increase-dementia-risk
https://www.npr.org/2020/11/16/935475284/scientists-discover-a-link-between-lack-of-deep-sleep-and-alzheimers-disease
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6286721/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651462/#:~:text=More%20specifically%2C%20when%20one%20sleeps,help%20maintain%20its%20normal%20functioning.
"Until recently, the latest research developments have concluded that sleeping has much more impact in the brain than previously thought. More specifically, when one sleeps, the brain resets itself, removes toxic waste byproducts which may have accumulated throughout the day [2]. This new scientific evidence is important because it demonstrates that sleeping can clear “cobwebs” in the brain and help maintain its normal functioning. More importantly speaking, this paper illustrates the different principles of sleep; starting from the non-rapid eye movement (NREM) to the behavioral as well as mental patterns with chronic sleep loss as well as the importance of sleeping acting as a garbage disposal in the body."
Edit 2: Yes I agree. Not just Quantity of sleep but Quality of sleep matters as well
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449130/
Edit 3: Amount of sleep required varies from individual to individual
http://healthysleep.med.harvard.edu/healthy/science/variations/individual-variation-genetics
Edit 4: For people saying nobody says that.
My mom did. I followed the 6 hour thing for very long till I realised, that wasn't true and I needed 7 hours. I used to wake up at 4.30 AM to push more hours of studies ( after 6 hour sleep) man let me tell you. I was extremely sleepy and tired in class. I stopped doing that later. Couldn't keep doing that.
When I was a teenager, they never let me sleep over 8AM, even during summer holidays.
About Boss and Coworkers....In 5 months I'll become a doctor. Healthcare, depending on your speciality and job is one sector where sleep and mental health is actually ignored. I see my interns/ house surgeons staying awake 36 hours. Sometimes the job requires it. Night duties are a part of the job. Even during our undergraduate it's considered very normal to lose sleep over studying for tests and exams. Most of them sleep hardly 3 - 5 hours before University exams. It has kinda become the norm. And yes I've heard my own friends bragging about how less they slept the previous day. It's pathetic.
In our student life these kinda extreme situations happen before exams and our exams go over a month.
(Credits to reddit post, see image above)
When we don't have exams, I keep my sleep the highest priority more than my studies and try to eat well and exercise. I'll take the stress when I have to, just before the exams.
During internship, half the interns I see are sleep deprived and stressed.
Brings me to another point. It's not possible to have a good sound sleep all the time, but we can have good sleep atleast most of the time.