We all know not sleeping enough is detrimental to our health, happiness and productivity.
Over the last couple of years in particular we’ve been bombarded by books, magazine articles and wellness gurus telling us there’s a “global sleep crisis” and lack of sleep is the single biggest threat to world health.
Unfortunately the situation could be even worse than anyone thought. A recent sleep deprivation study, published in the journal Sleep, took 48 adults and restricted their sleep to a maximum of four, six, or eight hours a night for two weeks. One unlucky subset was deprived of sleep for 72 hours.
Sleep scientists already highlight the dangers of regularly getting less than 7 hours sleep a night, but the study found that subjects who got six hours of sleep a night for two weeks functioned as poorly as those who were forced to stay awake for two days.
We're not a great judge of sleep
To make matters worse people generally have only a tenuous grasp of how they’re actually sleeping. Research from the University of Chicago shows that people are as likely to overestimate how much they sleep as underestimate it.
A study published in Epidemiology indicates people generally overestimate their nightly sleep by around 0.8 hours. The same study also estimates that for every hour beyond six that people sleep, they overestimate sleep by about half an hour. So if you think you sleep seven hours a night it’s entirely possible you’re only getting six.
So no one knows how much or little they’re sleeping, and when they don’t sleep enough, they believe they’re doing better than they are. Wearable devices aren’t really measuring sleep at all so can sometimes exacerbate this sleep misperception, adding to the anxiety many people feel about their sleep and making it incredibly difficult to achieve a healthy sleep routine.
Why I talk about sleep when I'm a coach
People come to me when they want to change the direction of their lives. Maybe they are looking at a new career or relationship. Big decisions. And so it’s important that I feel that they are in the right place, mentally and physically, to make those decisions.
When people are sleep deprived or chronically stressed, their brain doesn’t function optimally, which means that they make substandard decisions. So it’s essential for life or career coaching to help clients sleep better so that they are able to make decisions that helps them achieve their goals.
You can learn more about how the brain operates under stress in this video.
How do you know how good your sleep is?
Sleep is when your body recovers from the mental and physical toils of the day. One of the best measurements of how the body is recovering is resting heart rate.
Heart rate during the night varies widely between individuals: it can be between 40–100 beats per minute and still be considered normal. It can also change from day to day, depending on your hydration level, elevation, exercise and temperature. As with many of the physiological metrics, such as heart rate variability, it’s often best to compare your heart rate with your own baseline, not with that of others.
Even though there is a lot of variability between individuals, night-time heart rates are very similar for one person – at least when you stick to regular habits. This is why nocturnal heart rate is one of the factors that you may trust when interpreting how your lifestyle choices affect your recovery. For most people, even a 4 bpm change marks a clear difference.
When you measure your heart rate through the night, typically you will see a “U” shaped curve on resting heart rate, as show in the figure below.
The hammock-shaped curve can be considered the optimal heart rate curve. During the first sleep cycles, your body relaxes and your blood pressure and heart rate drop. Your lowest heart rate happens at the midpoint of sleep when the amount of melatonin is at its highest. If you are perfectly aligned with the rhythm of the sun, your lowest basal body temperature also occurs around 4 am.
Note that your heart rate can momentarily rise during REM sleep. You can ignore these spikes when looking for the hammock-shaped curve.
Towards the end of the night, your heart rate starts to rise to prepare you to wake up. The hammock curve is a sign that your body was relaxed during the night, and ready to rise after a good night’s rest.
The Downward Slope is a sign that your metabolism is working overtime. Did you have a late meal, a late workout or a glass of wine before bed? If your resting heart rate starts high and reaches its lowest point right before you woke up, you may wake up feeling unrefreshed.
If you see the downward slope regularly, it’s a good time to stop and think if there’s something you could do differently. If you are a late exerciser, doing your physical training session 1–2 hours earlier can be a significant change, for example.
If your heart rate goes up right after you fall asleep, it may be sign that you’re too tired for bed. If it’s past your regular bedtime, you may start feeling the effects of your increased melatonin and lowered blood pressure as your body is trying to inform you about bedtime passing.
Perhaps you went to bed at a different time than usually? Also staying in bed later than normally reportedly leads to lowered cognitive performance the following day. Keeping a steady sleep routine really helps you get better sleep and perform better during the day.
Work out how much sleep is right for you
There’s a lot of guidance on the internet about how many hours sleep you need. And often that guidance is either right or not that wrong. But the best way to determine how much sleep you really need is to measure it.
I recommend the Oura ring for this purpose. It measures your heart rate and body temperature during sleep and gives you the best measurement of how much sleep you need in a consumer device today. You can find out more at https://ouraring.com/why-sleep-matters/
Sleep well and make better life decisions
So sleep is essential for living or creating a great life. No need to get stressed about it, just learn what you need and prioritise getting it. You’ll get more from your coaching, and more from life.
#lifecoaching #stress #sleep #biometrics