Dr. Matthew Walker, the author of the book Why We Sleep, was recently interviewed by Chris Anderson, the curator of the TED Conference for a virtual TED talk. The video is an hour long, but if you don’t have time to watch the whole thing, that’s why I’m here to give you the highlights.

The first point Dr. Walker makes is that he doesn’t want to feed into the anxiety loop that can make sleep even worse. Worrying about getting good sleep can itself disrupt your sleep

There is an intimate relationship between your sleep health and immune health. He listed some examples. 

• Individuals who reported getting less than 7 hours of sleep had almost a threefold increase in getting infected with the rhinovirus (common cold) compared with people who slept 8 hours or more. 
• A study of 50,000 women found that individuals getting 5 hours of sleep or less had a 70% increased risk of getting pneumonia relative to people getting 8 hours or more. 
• If you are not getting sufficient sleep the week before your flu shot, you produce less than 50% of the normal antibody response, rendering the vaccination significantly less effective.

Sleep is crucial for learning, memory, and creativity. You need to sleep before learning to prepare your brain to learn well. You need to sleep after learning to keep the new memories in the brain. Sleep allows the brain to integrate new memories with existing memories. 

You are never told to “stay awake on a problem.” The saying has always been to “sleep on it.” 

In addition to improving memory and creativity, sleep also helps your brain process emotional experiences by essentially providing an overnight therapy session.

“A ruffled mind makes a restless pillow.” –Charlotte Brontë

In the past 20 years, we have not found a single psychiatric condition under which sleep is normal.

Sleep has a big impact on hormones, particularly two hormones that control appetite.

Leptin is the hormone that signals that you are full.

Ghrelin is the hormone that signals that you are hungry.

When you have insufficient sleep, leptin goes down and ghrelin goes up. Not only are you getting the message to eat more, but also the cravings are for “bad” foods such as processed foods, sugar, and often foods devoid of nutrition.

We’ve all had the experience of being sick and wanting to just sleep. This is by design. Part of the immune system’s response to fight infection is to induce sleep, which increases the effectiveness of the immune system and stocks up the “supplies” of the immune system to keep fighting.

Physical activity during the day has a relationship with the quality and quantity of sleep that night and it works bidirectionally. Regular physical activity promotes sleep, and a good night’s sleep makes you more likely to engage in physical activity.

Stress causes the hormone cortisol to increase. This hormone should be reaching its lowest level right as we fall asleep, but in people with sleep onset insomnia, cortisol starts to increase around bedtime. Stress also activates the “fight or flight” branch of the nervous system, which makes it difficult to fall asleep or stay asleep. Meditation is a practice that can help with both of these issues.

Electronic devices are not a good idea near bedtime. The screens emit blue light, which could delay the release of melatonin. One study showed that people using an iPad for one hour before bed had a delay in melatonin release by 2-3 hours, and the amount of melatonin was about 50% less compared to someone reading or doing an activity without looking at a screen. The other issue is that reading news or checking social media could stimulate you at a time when you should be winding down. 

Checking your phone when you first wake up is also not a good idea. It can create something called “anticipatory anxiety” where the brain starts to expect the rush of stress associated with looking at news or social media first thing in the morning.

Alcohol is the enemy of sleep. Alcohol is a sedative, but sedation is not sleep. Alcohol-induced sleep is not the same as regular sleep. Alcohol causes sleep fragmentation, meaning you tend to wake up more often during the night. Alcohol also blocks the dream state of sleep called REM sleep.

Dr. Walker’s tips to get better sleep:

• Control the light in the evening by dimming lights and avoiding blue light from electronic screens.
• Make your bedroom cool.
• Be mindful of caffeine and alcohol consumption.
• If you have a bad night of sleep, resist the urge to sleep in. Wake up at your normal time even though it’s difficult. Avoid naps during the day if you have sleeping issues. Go to sleep at your normal time that evening.
• If you’re in bed and awake for 20-30 minutes, stop trying to fight with sleep. Get out of bed. Go and do something relaxing until you get sleepy, then return to bed.
• Have a wind-down routine. Going to sleep is like landing a plane. 
• Take a hot bath/shower. The hot water causes blood circulation to increase at the surface of the skin, and when you get out the heat is radiated away from the body causing the core body temperature to drop, which helps you fall asleep faster and stay asleep.
• Remove all clock faces from the bedroom. If you are having struggles with sleep, it is not helpful to have easy access to obsess about the time.