sleep

Everything I’ve read about fitness and sleep during the past ten years has talked about the major importance sleep plays in rejuvenating our body — lack of sleep can be as harmful as eating unhealthy foods! While I’ve been trying to change my schedule to wake up earlier, I often find myself waking up extremely tired. I justify going back to sleep because I tell myself it’s probably healthier than waking up early. But then if I don’t deal with lack of sleep for a few nights in a row, I’ll never adjust my sleeping pattern. 

One just has to look at anyone with untreated sleep apnea to see just how dangerous it is. You can easily identify such people just by looking for the signs... darkened eye sockets, labored breathing, swelling of the legs and body, disorientation, lethargy and bruising.

And it's not just difficulty sleeping either, the body ends up literally consuming more energy trying to sleep than it does while conscious. The lack of oxygen in the circulatory system fools the body into overproduction of red blood cells to compensate. This, in turn, leads to a dangerous shift in blood pressure to the point that the heart may cease to function under the load (chronic-conjestive lung and heart failure).

In many cases, those suffering from it are often discovered with blood oxygen levels lower than that of a cadaver.

One thing to remember though, is that the act of sleeping isn't just merely closing the eyes for a few winks, the body *needs* to rest lying down to recover from the negative effects of being upright all day. Blood that is left to pool in the legs for too long can eventually lead to dangerous blood clots.

In my early thirties I started snoring a lot, and very heavily. Two years later I started experiencing symptoms such as forgetting where I was going as I driving down the road, getting into my vehicle and not remembering how to start it, forgetting my own phone number, the inability to perform my job at any level of competency, etc.... I thought I had suffered a major stroke.

I went to the doctor and he said I was a ringer for sleep apnea and referred me to a sleep clinic.

Long story short I was waking 50 times an hour because that's how often my breathing was being interrupted and my body would rouse me due to low oxygen levels in my blood. To me it seemed as if I was awake all night long and never went to sleep.

After being fitted with a cpap mask and sleep machine to pump air into my mouth and nose while I slept it took me three weeks of normal sleep to recover my mental faculties.

Sleep deprivation will kill you, and it will also seriously degrade your mental capabilities. It's nothing to mess around with. In addition to the mental problems the probability of a stroke or heart attack is greatly amplified.

I think the biggest thing you need sooner or later is REM sleep, not just a lie down. Lack of REM sleep (which, as we'll see is possible while technically still getting some sleep) can result in actual brain damage, or in the very long run even death. (Ironically, it's also produced _by_ certain kinds of brain damage.) Also, while we still lack the complete picture, it's proven that at least one type of memory isn't updated without REM.

REM sleep also doesn't come instantly. In most people you need at least 90 minutes from falling asleep to having your first REM period. Anything under about half an hour is a sign of narcolepsy. Your longest REM episodes happen after several hours.

On the average over a whole night, about a quarter of the time will be REM. It's safe to assume that in the long run those two hours or so of REM a day are what your body actually needs.

But again, you don't get them in one big chunk. You get them interleaved with periods of non-REM sleep. So what it boils down to is that to get your normal quota of REM sleep, you'll actually need those 8 hours a night. You might get by with just 7, but anything less (unless you're over 70) is putting stress on your brain in the long run. You might not outright die, but you won't be very smart or attentive after months of getting significantly less.

No, the most essential type of sleep is slow-wave sleep, which is even mentioned [nytimes.com] in TFA.

I've done some computational modelling of the cerebral cortex, and my hypothesis [bigpond.net.au] (page 7/139) is that slow-wave sleep is used to re-strengthen competitive connections between cortical columns, restoring the ability to think clearly.

Morbidity, [or sickness,] is also "U-shaped," in the sense that both very short sleep and very long sleep are associated with many illnesses - with depression, with obesity, and therefore with heart disease and so forth. But the [ideal amount of sleep] for different health measures isn't all in the same place. Most of the "low points" are at seven or eight hours, but there are some at six and some even at nine. I think diabetes is lowest in seven-hour sleepers, [for example]. But these measures aren't as clear as the mortality data.