Theory Thursday

Sleep and Stress Management

Good evening!  Hopefully you’ve got a blue filter, now, on your screen so you can read this without triggering wakefulness.  Apologies for the error in Tuesday’s blog (now corrected) – Melatonin (a Pineal gland hormone) helps sleep and blue light inhibits it, that’s why you need your blue light screen filter.

And why do you need sleep?  There is a body of evidence mounting that 6-9 hours a night is beneficial for your waistline – good quality zeds can help regulate your metabolism and your appetite and that, of course, is the nirvana we seek to stay healthy.

How to sleep well

There are a number of facets to sleeping well, and modern life mostly tries to override all of them!  Which makes it a perpetual challenge to get good “sleep hygiene”, even when you know what you ought to be doing:


You sleep better if you always go to bed & get up at the same time.  A weekend lie-in, as tempting or necessary as it feels, could set your sleep pattern off kilter.  There is mixed evidence about naps (20 mins or 90 mins refreshing you, but for the elderly who take naps there is an association with mortality – possibly because the cause of the naps is high pharmaceutical load signalling high morbidity), so it could be better to carry on setting your work alarm at the weekend and compensate with an afternoon power nap if you need to, but just set the alarm nice and late, but at a regular time every day, if you’re retired.


The ideal bedroom temperature is 18 degrees C, rather cooler than your living room at 21 degrees.  The body knows it ought to sleep as it cools so having a bath before bed which warms you in order to then cooldown afterwards can help, too.


We’ve mentioned melatonin.  We wake with blue light and melatonin gets triggered with sunset (warm light) & darkness to send us to sleep.  Modern life so overrides our natural rhythms, especially in winter that it helps to have the blue light filters at night that we mentioned and in the morning to have an alarm with a daylight-mimicking light to help wake us.


fruit & low fat yoghurt = carbs & tryptophan

We’ve been avoiding carbs, or being very selective about carbs, but they can help you sleep when consumed with protein due to helping sleep-inducing tryptophan (amino acid from the protein) become more available to the brain.  But pick your carbs wisely!  Some micronutrients help sleep, too – Potassium, Magnesium and Calcium – by calming restless muscles and promoting relaxation.  So banana with milk is good, as would be tuna and sweet potatoes for dinner.

How long should you eat before retiring to the land of nod?  The answer is, it depends what you eat.  Anything fatty will take a long time to digest (hours) but a lean protein/carb combo to get your tryptophan in can be taken right before bed.


Warm milky drinks – why do they work? See above re tryptophan

How long should you drink before bed?  As above, milk is pretty low in fat (even “full fat” is only 4%) so go for it.

Alcohol – see below


Caffeine is the enemy, of course.  How long should you be caffeine-free before bed?  Well, it depends!  The “half-life” of caffeine is 5-6 hours (of the 225mg caffeine in your starbucks cappucino ingested at 08.00, 112.5mg will still be circulating inside you at 14.00 and 56.25mg at 20.00 and 28.125mg at 02.00!).  Black tea has got approx. 30mg per tea bag, a small costa coffee latte has 92mg (their large mocha has a whopping 395mg!) and even coke “zero” has got 34mg.  (By the way, the lethal dose of caffeine is 18g).  Do your own maths, but I will try not have any caffeine after breakfast after working on this!

Alcohol is a great sedative.  It will get you off to sleep a treat, but when it wears off at 4 a.m. you feel terrible & terribly wakeful.

Stress Management

The other thief of sleep is stress.  We’re all psychologically stressed by modern life, but our body perceives this as requiring a fight or flight response and triggers cortisol (the counterpoint hormone to melatonin) which makes you wakeful, and prone to “early morning waking” at 4a.m.

Good stress management with yoga or meditation, Qi Gong or Tai Chi can mitigate this, according to a variety of evidence.  There are many types of meditation, but all involve clearing the mind of stray thoughts and concentrating on either the here and now/your breathing or a “mantra” (repeated word/phrase).  It’s actually rather challenging and requires practice, but you don’t have to go the whole hippy hog to benefit.  Try the 4-7-8 breathing cycle tonight (in 4s, hold 7s, out 8s) as you’re falling asleep and see if your tracker tells you that you dropped off more quickly.

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