Key to losing weight is a good night’s sleep

In the final part of his 4 Pillar Plan, Dr Rangan Chatterjee tackles the most undervalued area of good health: sleep

All three of the previous pillars feed directly into this one, and vice versa. When you sleep well, it’s much easier to make better choices the following day. You crave less sugary food and feel more energetic, which, in turn, means you’re inclined to be more physically active on the one hand, and to engage in relaxation practices such as meditation on the other. Such behaviour is selfreinforcing: when you’re more physically active, eat healthy food and prioritise relaxation, you’ll sleep even better.

I believe that sleep is arguably the most undervalued component of health in today’s society. It is well recognised now that even short-term sleep deprivation causes increased levels of the stress hormone cortisol and raises blood pressure, while plenty of studies also link it to obesity and type 2 diabetes.

Unfortunately, we can’t dodge the effects of sleep deprivation by having a bit of a lie-in on a Sunday morning. Studies show that we accrue “sleep debt”, which we can’t just repay with a couple of cheeky extra hours here and there. Many of my patients find that, most of the time, choosing three of the following five interventions seems to be enough to consistently get a better night’s sleep.

1 Create an environment of absolute darkness

Darkness is a signal to our bodies that it’s time to rest. It triggers the production of melatonin, the hormone that’s largely responsible for helping us go to sleep. And yet too little light in the morning and too much at night is increasingly the norm these days. This is why I strongly recommend installing blackout blinds or extra-thick curtains and trying to keep your bedroom completely dark and free of televisions or e-devices, which emit the same wavelength of light as the morning sun. Even a glance at the light a smartphone emits can impact melatonin secretion.

At home, my wife and I have tried to institute a rule that says unless there’s some kind of exceptional circumstance, our phones and laptops go off at 8.30pm and we don’t bring them upstairs. If you really must look at smart devices late at night, I’d recommend buying some amber glasses, which help to filter the blue light from your screen even better than “night-mode” apps and can be bought online for as little as £10.

2 Spend at least 20 minutes outside every morning

Prioritising sleep starts the minute we get up and one of the best things we can do is get outdoors in natural daylight. Our exposure to the sun (or even natural daylight) in the morning is critical for feelings of well-being in the day but also for good quality sleep at night.

Over the past two years, I’ve even found myself persuading some of my patients to have their morning cup of tea in the garden with a fleece on. Even on the dullest days, we’re still exposing ourselves to light at a higher amount outdoors than if we were inside.

An observational study from 2016 followed the health habits of nearly 30,000 women and found that smokers who had a high degree of sun exposure had the same risk of mortality as non-smokers who did not expose themselves to the sun. I know it sounds almost crazy, but I truly believe companies should start giving staff regular light breaks.

One of the great things about this intervention is that you can combine it with others. If you use this time outside as your daily workout, you’re ticking off another box in the Move pillar. It also helps with “me-time” from the Relax pillar, and you are more likely to reach your 10,000 steps a day. Either way, if you make light a priority, I promise you will very quickly start to feel the difference.

3 Create a bedtime routine (and embrace napping)

Just as important as having a set getting-up time is having a fixed routine for going to bed. Set a bedtime alarm for 90 minutes before lights out. As soon as it sounds, start your evening wind-down with a “No-tech 90”: turn off all your e-devices, including computers. No exceptions.

Sticking to the same bedtime constantly is not always going to be possible, whether it’s due to a party, dinner date or work engagement. In these situations, I make one simple recommendation. No matter how late you go to bed, no matter if the next day is a Monday or a Sunday, always get up at the same time. Of course, you will have missed out on sleep, but for most of us, staying in sync is better than catching up in the morning. Instead, embrace the habit of napping – be it for five minutes in your car all the way up to two hours in bed. The space agency Nasa found that if co-pilots took a 26-minute nap their alertness improved by 82per cent.

4 Manage your commotion

For the majority of sleep problems that I see, “emotional commotion” (in common parlance, getting a bit wound up) in the last part of the day plays a big contributory role. Managing your commotion means making it a cast-iron rule that you do not discuss emotive subjects in the evenings, crack into a new work task or check your bank balance. A racing mind is one of the biggest causes of suboptimal sleep.

Of course, it’s very hard to diarise an argument with your partner, but if you know you need to have a difficult conversation, don’t have it at bedtime. I don’t respond to anything but emergencies after 8pm.

Exercise, too, can count as commotion. Although a few people find that vigorous exercise in the evening doesn’t affect their quality of sleep, for many of us it can be problematic – raising cortisol levels at exactly the time of day when they should be falling. Eating into our “switch-off ” time harms our sleep quality, which means we can’t perform efficiently during actual working hours.

5 Enjoy your caffeine before noon

Caffeine is the world’s most popular drug, but there’s a gene called the CYP1A2 that helps determine how quickly we break caffeine down. If you’re one of the lucky ones who metabolise it up to four times faster than others, you’re also more likely to get many of caffeine’s benefits, which include lower risk of stroke, Alzheimer’s disease and heart attack. But if you metabolise it more slowly, it’ll stick around in your body for longer and that may make you more vulnerable to its adverse effects, which include irritability, anxiety and sleep disruption.

It’s no surprise, then, that many people sleep a lot better when they quit caffeine completely. Evidence is now suggesting that even if you can fall asleep after an evening caffeine hit, you don’t access the deep levels of sleep that you need. The reality is, if you think your sleep could be better than it is, implement a midday watershed. Drink non-caffeinated herbal tea to get you past your afternoon slump (remember, green tea contains caffeine) or swap for sparkling water.

Adapted from The 4 Pillar Plan: How to Relax, Eat, Move and Sleep Your Way to a Longer, Healthier Life by Dr Rangan Chatterjee, published by Penguin Life (£16.99). To order your copy for £14.99 plus p&p call 0844 871 1514 or visit books.telegraph.co.uk