How to sleep better, according to a sleep scientist
We speak to a sleep expert on the importance of shut-eye—and how to get 40 winks.
Evolution gives us a pretty good indication of how important sleep is for the brain. Instructions for a daily sleep are hard-wired into our DNA. We can survive for longer without food than without sleep.
Why do we need sleep?
So what was the evolutionary advantage for our cave dwelling ancestors to lie down with our eyes closed, as predators prowled around outside? Why haven’t we evolved not to sleep? Even for today’s workaholics, the idea of ‘switching off’ for the recommended 7-9 hours each night can feel like a threat to career survival…
We need to stop thinking about sleep as switching off. Quite the reverse. Sleep is an active process for repairing, and enhancing, brain performance. Even a cheeky 10 minute nap can improve mood and memory.
An ironic quirk of sleep deprivation means we tend to underestimate how much lack of sleep affects us. Driving a car after 19 hours without sleep will put your co-ordination and reaction time on a par with a drunk driver.
Sleep and immunity
A PNAS study showed that sleep can have a tangible effect on the immune system. A healthy group of adults were limited to 6 hours of sleep a day for a week—this is the average amount of sleep typical adults get. These were compared to subjects who got 8 hours sleep, and a change in activity of 711 genes were reported. Half those genes were upregulated, and half were downregulated. Downregulated genes are associated with the immune system, and upregulated genes are associated with tumor production, long-term chronic inflammation, and cardiovascular disease.
If nothing else, this demonstrates how powerful sleep is. It is health insurance—you should invest in it.
Sleep loss can also mean we lose some fundamental human qualities
Emotional balance: Feeling stressed? Short sleep signals the brain to be hypersensitive to threat. We become more emotional, argumentative, and vulnerable to anxiety and depression.
Self-control: While the sleep-deprived brain is being hijacked by emotion, it dials down less essential functions for survival—such as long term planning, or sticking to our eating goals. We make more impulsive decisions, and—given the temptation—are more likely to cheat, or be ‘deviant’ at work.
Learning and memory: Sleep is the process through which important memories are consolidated, and others are pruned back, freeing up more space to learn the next day. Deep sleep also has a cleansing effect on our memory banks, cleaning out toxic proteins like beta-amyloid, which accumulates in Alzheimer’s disease.
Some people are genetically programmed to thrive on fewer than 7 hours sleep, but they’re in the minority. If you wake up without an alarm, feeling refreshed, don’t rely on caffeine or stimulants to pep you up, maintain enough energy throughout the day, and don’t ‘catch up’ on sleep at the weekend, your sleep is probably in good shape.
For everyone else, try R.E.S.T.
This is the simple, four-step programme that everyone can try, to sleep longer, and better.
1. Routine: Stick to routine wake times, >5 days a week
Two independent processes control your sleep. Firstly, there is a sleep pressure which builds up gradually the longer you’ve been awake. Secondly, there’s your body clock. In fact, every cell in the body has its own molecular clock, programmed to operate on a 24 hour ‘circadian’ rhythm. When we stick to the same wake up time and bedtime (even if you’re also juggling kids’ sleep times), our body clocks are more likely to hum along in synchrony. Haphazard routines, or night shifts, put more pressure on bodily functions, and mean the brain is less prepared for sleep. If a standard bedtime is a struggle, aim to wake up within an hour of the same time, 7 days a week.
2. Energise strategically with light, exercise and healthy food
A good blast of bright light in the morning helps us feel alert, whereas dimming the lights after sunset triggers the release of the hormone melatonin, which signals the brain that it’s time for sleep. This is extra-useful with kids too—avoiding the television or tablets in the hour before bed, and getting used to a dark bedroom from a young age, can help them get to sleep, and stay asleep. In winter, when the mornings are darker, it can be helpful to invest in a SAD lamp to mimic the effects of sunlight when it’s dark outside.
Exercise helps pep us up, and has the added benefit of aiding deep sleep at night. Food also sends a wake-up signal, so avoid large meals two hours before bed. Caffeine temporarily masks sleep pressure. Excess caffeine means you can lose track of how much sleep you need, and it can make sleep lighter. If you’re struggling with sleep, try switching to decaf, especially in the afternoon.
3. Switch off: wind down before bed
Parents know that a consistent bedtime routine is essential for their hyperactive toddlers, but it’s good news for adults too. Give yourself an hour to unwind—that means no more work, no phone and no bright lights. If stress is the issue, and your mind won’t stop racing, there are several things you can do. Try a breathing exercise, or put a piece of paper and a pencil by your bed. Then before you get into bed, spend 10 minutes writing down what’s on your mind. If those thoughts pop up, tell yourself they’re on the page, and let them go.
Your sleep environment? Think luxury cave. Dark, quiet and cool—about 18C. (I’ve never seen a cave with a TV...) A drop in body temperature is a cue for sleep. A recent study found that taking a warm bath 1-2 hours before bed aided restful sleep—not only does warm water help your muscles to relax, the cooling that takes place as you exit the bath could help to induce a restful slumber.
Sleeping pills and melatonin
In general, you should do everything possible to avoid sleeping pills. Studies link a higher risk of death and cancer with taking certain sleeping pills. Occasionally, though, they might be recommended by a medical professional. This is because they can help you to start on the path toward consistent sleep. But they aren’t for long-term use, and can lead to sleep walking, sleep talking, and potentially an increased risk of age-related diseases. They’re also sedatives, so you aren’t even getting the high-quality sleep that we all need.
Similarly, melatonin supplements can be helpful in the short-term, but should not be relied upon to provide consistent relief. To get high-quality sleep, long term, your body needs to produce its own melatonin, and taking melatonin supplements inhibits that process.
Who is Sophie Bostock?
Dr Sophie Bostock is a sleep scientist, turned Sleep Evangelist.
Following degrees in Medicine and Entrepreneurship, she completed a PhD in Psychobiology at UCL, which launched a fascination with sleep as one of the unsung heroes of wellbeing and performance.