Hacker News Reader

Comment by brd | Hacker News Reader

"Sleep is important" has been a recurring theme for the last couple of years but I am one of the few that don't buy into it at all. Maybe I fall into the 2.5% but if I sleep 8+ hours I feel overslept and groggy. I function moderately to exceptionally well on 6 hours of sleep and often times end up getting more like 3-5 hours of sleep.

I've read articles about high functioning executives that barely sleep at all and seen studies about less sleep improving lifespan along with all the standard sleep is so important articles. I think its safe to say the jury is still out on this subject and keep hoping it doesn't continue to over saturate the news/science pipeline for much longer. Until there is a definitive answer you'll continue hearing me say "sleep is overrated".

View on HN

I agree for the most part. However, try going for a regular run (say 5km) once per week, same day, and track your times. Let's say you hit about 30 minutes first time, and get it down to around 20 mins over a couple of weeks. Now try greater sleep deprivation than normal one week and watch your time plummet.

I find the same sort of result with coding on little sleep. While it feels like I'm "high functioning" while coding at 4:00AM, a code review in the light of day after a good night's sleep often reveals that I wasn't.

I've begun to suspect this is because we don't notice all the little issues we'd notice if we were more awake - at 4AM, the code is Flying, because I'm not stopping to realize how crappy the code is.

I've had similar experiences. If I am very tired I don't get "coder's block", but the code is often rubbish.

It's well known that sleep is an absolute requirement for athletes. If you don't get an optimal amount, performance will suffer: http://sportsmedicine.about.com/cs/conditioning/a/aa062800a....

If it affects peak physical performance, it seems reasonable to suspect it affects peak mental performance (as studies seem to suggest). High functioning executives might get by on little sleep, but would they perform better on more sleep? Are hours clocked more important than output at the executive level?

No, it doesn't seem reasonable at all.

Athletic activity causes actual physical microdamage that takes rest time, nutrition, and hormones to repair. The elevated secretion of human growth hormone during REM sleep is a significant reason why athletes perform better on more sleep.

No such analogue exists for the human brain. Mental activities, at worst, deplete neurotransmitter levels. I have seen no evidence to suggest that massive dosages of sleep do a better job of restoring these levels than minimally adequate amounts.

I thought it was well known that sleep plays a very important role in learning?

For mental work, sleep is not replenishment, it's prep work. Your brain is thinking problems while you sleep.

Not only that, sleep also appears to be when your brain reinforces what you've learned... over and over again.

Yet people perform worse mentally without sleep - why would that be if sleep was not vital to mental performance? Have you never needed a nap or coffee to refresh your mind? Do you deny a physical influence on mental faculties?

Training involves neural adaptation, a large part of which occurs while sleeping.

The systems of the body are not neatly partitioned into modules.

Considering I used to run Xcountry and have been known to go out for 8+ mile runs in the middle of the night, I'd say for the most part my sleeping habits do not impact how I feel while running. In fact, I'd actually say more exercise is more important than more sleep as I feel much better in general when I am exercising/running regularly, regardless of my sleeping habits.

I will absolutely concede that there is a threshold where sleep deprivation will negatively impact my (or anyone's) ability to perform, its just a question of what that threshold actually is.

I need 8 and often more like 9 or 10 hours of solid sleep each night. If I'm well-rested, one night of 6 or 7 hours doesn't affect me, but it can't happen repeatedly. We may both just be outliers.

"sleep is important" is a lot different than "8+ hours of sleep is important." I'd agree with the former, but agree that the latter is dependent on the individual. Anecdotally, I definitely agree that oversleeping makes meore groggy.

> I've ... seen studies about less sleep improving lifespan

The surveys I can find associate "normal" amounts of sleep with better lifespan, and both abnormally high and abnormally low levels of sleep (<5 or 6 and >9 or 10 hours, depending on the study) with various negative outcomes. E.g. this meta-analysis pools prospective studies looking at heart attack and stroke rates: http://eurheartj.oxfordjournals.org/content/early/2011/02/03...

Depending on where you look the golden rule for longevity seems to be 6-7 hours of sleep. The interesting thing about 7 being the more common number is that 7 doesn't fit into the commonly held belief that sleeping in sync with 90 minute REM cycles is more healthy/effective. Example of study saying 6-7 hours: http://www.worldhealth.net/news/six_to_seven_hours_sleep_bes...

Most of what you site is anecdotal evidence. Most likely, you and those executives fall into that 2.5% cohort.

> ... seen studies about less sleep improving lifespan...

Sleeping less than your own individual sleep need probably does not improve life span. The participants in the studies you're referring to who slept vastly more than others were those with sleeping disorders, some with extremely bad sleep apnea. They felt the need to sleep more because the quality of their sleep was so poor. But of course, having a lot of poor-quality sleep is not equivalent to having fewer hours of good-quality sleep.

The contribution I would like to make to this discussion is that each person's sleep need is individual.

I am in absolute agreement with this. I find that if I sleep more than 6 hours a night, I am actually more tired the following day.

Normally, I get 5 hours per night and I rarely experience low levels of functioning or excessive fatigue.

And as other have pointed out, the methodology of the cited experiment in the article is highly suspect. Any normal human being, locked in a room with no stimuli, is likely to sleep as much as possible to pass the time.

At a time when I was sleep deprived I felt completely OK. When I caught up on the sleep I felt worse. I think it's because sleep deprivation also deprives you of the ability to notice the negative effects well enough.

That's probably not what's happening with you if you naturally sleep 5 hours per night without an alarm though. If you are using an alarm, you should try sleeping as long as your body feels like for two weeks. Don't block sunlight from your windows, let the sun make sure you wake up if your body thinks you've slept enough. If your body thinks you are still not rested, it will keep you asleep even in sunlight.

Reply on news.ycombinator.com