Dr Chatterjee on sleep

‘Sleep is the biggest improvement in my health’ // The Guardian

Sleep is key to our wellbeing. It prevents illness and injury, improves our mood and concentration, and gives us energy and motivation. So how can we ensure we get enough zeds? M&S sleep ambassador Dr Rangan Chatterjee reveals all to Kate Faithfull-Williams

Sleep – crucially, the lack of it – affects the majority of my patients. But most people completely underestimate the importance of sleep. Patients often come in with another complaint, such as anxiety or stress, then when we delve deeper it’s clear that sleep is a big factor to address.

Sleep affects every single organ in the body, from our brains to our stomachs, our sexual organs and our skin. So when we’re not getting enough sleep – and over half of us have felt stressed from fatigue, according to research from Oxford University [pdf] – it affects our mental health, digestion, fertility, immune system, mood and more.

Let’s talk about our brains first. When we don’t sleep well, our amygdala, the emotional part of the brain, is up to 60% more reactive. In other words, we feel anxious, stressed and overreact to everything. But when we sleep well our mood improves, as does our concentration, memory and our ability to process what’s happened in our day. Getting enough sleep can even help protect us against dementia.

When it comes to physical health, I believe we’ve given too much attention to diet and exercise at the cost of sleep. Yet a single night of sleep deprivation can raise levels of the hunger hormone, ghrelin, and reduce the satiety hormone, leptin. So if you’re tired, you constantly feel hungry and never feel satisfied.

Sleep also affects athletic performance, and I don’t mean just Olympians. You can run faster, lift heavier weights and are less likely to get injured after a good night’s sleep. And don’t forget the obvious: sufficient sleep gives us the energy and motivation to exercise.

One more really important benefit: a stronger immune system. Night-time is when our bodies repair and restore cells. Sleep is one of the best things you can do to avoid getting a cold, and if you’ve already succumbed to sneezes then sleep is your best route to recovery.

So, what can we do to get the sleep we need for a happier, healthier life? We can start from the moment we wake up, by getting outside for 20 minutes of natural daylight. Our circadian rhythm works with contrast in light, so the more daylight you get in the day, the more robust your sleepy phase will be at night.

Sunshine exposes us to 30,000 lux (the measurement of illumination). Even on a cloudy autumn day, you get 10,000 lux. Artificial light cannot compare – even in a brightly lit office, you’re only exposed 500-1,000 lux. If it’s dark when you’re up in the morning, be sure to get outside for 20 minutes at lunchtime.

We have to talk about coffee. Much as I love my coffee, science shows it’s one of the biggest sleep disruptors. The trouble is, the time taken for the body to eliminate one-half of the caffeine is six hours, which means if you’re having a latte to push through your afternoon slump, it’s effectively like having half a coffee at 9pm. My rule is to stick to one or two cups, and enjoy your caffeine before noon. Don’t worry; you’ll depend less on caffeine for your get-up-and-go when sleep gives you energy instead.

Stress is a huge factor, and it has a bidirectional relationship with sleep. Not sleeping well is one of the biggest stressors on the body on a cellular level, and stress is the biggest reason why we can’t sleep. This makes sense to parents, as we know kids need a calming bedtime routine. But we forget that we need to wind down before bed too.

Before we discuss how to unwind, let’s bust a big myth. Alcohol does not help us sleep. Alcohol causes sedation, which doesn’t share the same restorative benefits of sleep. In fact, studies show alcohol fragments and dramatically reduces our REM sleep, the critical dream phase. If you like a glass of wine to unwind, you’re better off drinking it straight after work at 6pm than at 10pm.

You knew screen time was going to come up too, right? The problem with tech is twofold: blue light from the screen reduces our natural melatonin, the sleepy hormone, and the emotional stimulation of our screen activity keeps us wired. I prescribe a tech-free hour before bed to help you drift off faster and sleep more deeply. But if 60 minutes sounds too much, start with 10. Honestly, even if you think you fall asleep OK after a bedtime burst of emails and social media, you’ll notice you feel far better in the morning when you’ve stuck to a tech curfew.

Take it from someone who knows. The biggest improvement in my health in the past four years is that I get a solid eight hours most nights. I feel great for it. I‘ve done a lot of self-experimentation and I’ve found going on to night-time mode at 8.30pm is the key. I switch off my laptop, leave my phone on charge downstairs and open a book instead. I’m almost always asleep by 10pm.

But I’m not perfect – I was on my phone last night before bed, and guess what? I didn’t sleep so well. Counterintuitively, the best way to reset your sleep rhythm is to still get up at the same time. So that’s what I’ve done today, and I’m already looking forward to going to bed tonight.

The M&S Sleep Shop has everything you need for a great night’s sleep. To find out more go to marksandspencer.com/l/the-sleep-shop or visit a Sleep Shop in your local store.

Dr Rangan Chatterjee is the author of The Stress Solution. Listen to his podcast on sleep here: www.drchatterjee.com/70