"Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer."
Matthew Walker, Why We Sleep: The New Science of Sleep and Dreams
How do you feel about your sleep?
The distress that goes with losing sleep, having disrupted sleep, or just feeling that in some way your sleep is unsatisfactory results in a great deal of angst. People are increasingly preoccupied with sleep. Fair enough. Getting the right amount of sleep on a regular basis could be the single best life hack there is.
I’m a bit obsessive about sleep, too. I’ve a regular routine and my sleep suffers when I step out of that routine. Other than the occasional bout of jet lag, I’ve never suffered from insomnia but I've had my share of sleep deprivation so I’m no stranger to that discomfort. I’ve worked as a junior doctor, done countless on-call shifts where I’ve been dragged out of my bed in the middle of the night, and been part of rosters involving long stretches of nights and antisocial shifts. When I worked in the Emergency Department we used to work a series of shifts that included the dreaded 8pm- 4am.
I have children who came in a tight grouping and at one stage I had three children under three. There were years where I didn’t get an unbroken night's sleep. I've been in the British Army, where sleep deprivation is regarded as a necessary element of any exercise to test out training. There’s a reason for that: it’s the single easiest way to ramp up the intensity of training and test your ability to function under duress.
I hate not sleeping. I find it easy to believe that shift work shortens your life. It is unspeakably stressful.
Some sleep basics
We go through different cycles while we sleep. Each of the cycles will last for something like 90-120 minutes. Typically the two main types are rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). There are distinct physiological differences in things like your brain waves, eye movements, and muscle tone during each of these phases. Changes in NREM can be sub-divided into three different stages that are progressively deeper. In a typical night of sleep deeper NREM sleep tends to dominate at the start of the night and REM sleep is more common in the second half. As we age, we spend less time in the deeper stages of sleep and it is normal to wake up more often.
Sleep and resilience
Loss of sleep results in problems with using your brain, known as cognitive impairment. That’s well-established. It has also been shown that we are not, ourselves, very good judges of that impairment. This is a worrying combination. There can be a strange kind of bravado associated with missing out on sleep, and the inability to realize that it damages how our brains function puts an interesting spin on this.
Evidence related to health and sleep deprivation
"Insomnia became the norm. I would lie down to try to sleep at a normal hour, but then it was like I had a tape in my brain that was on permanent fast forward and refused to shut off."
Halona Black, The Healthy Writer survey
What does it mean to not get enough sleep? What does it do to your body?
It slows up your cognition.
Putting it bluntly, it makes you a little bit more stupid than you otherwise would be.
It also dulls your reactions in the same way as drinking some alcohol. Even one night of disrupted sleep makes you more likely to have an accident driving the next day. Several nights without sleep will leave you feeling grotty. Sleep deprivation has a grisly history in its use as a form of torture.
There is a lot of evidence about the health effects of sleep. A reduction in the number of hours of sleep can have an impact on cardiovascular health, your risk of cancer, and your mental health. Obviously, this is fairly complex research and there are lots of conflicting and compounding factors. People who are ill often have worse sleep, and teasing them out of the research is difficult. The challenge with sleep is always working out whether it is causal or whether it is a symptom of some other problem.
There is evidence that prolonged periods of poor sleep or loss of sleep will result in increases in blood pressure. The wider health implications of prolonged periods of sleep loss or disruption are severe. Night shift work increases the risk of breast cancer and shift work of all kinds is associated with an increased risk of events such as heart attacks and strokes.
Tracking your sleep
As with so many things, monitoring and keeping a record is an important step toward working out what to do.
It can take any form you want, but the American Academy of Sleep Medicine has an example of a sleep diary format. A popular option these days is to use some kind of wearable technology such as a fitness tracker. These will usually tell you how long you have been asleep and will also provide little graphs of your sleep cycles including deep sleep, light sleep, REM sleep, and awake periods. We'll go into more ways to help your sleep in Part 2.
Questions:
- How much sleep are you getting every night? Do you feel that is enough for you? Are you going through life with a constant sleep deficit?
- How often do you wake up naturally without an alarm or interruption?
- Have you tracked or monitored your sleep?
Resources:
- American Academy of Sleep Medicine – 2 week sleep diary www.yoursleep.aasmnet.org/pdf/sleepdiary.pdf
- Sleep Junkies website – www.sleepjunkies.com
- Why We Sleep: The New Science of Sleep and Dreams – Matthew Walker