Science of Sleep

Guidance from yoga and psychology for your best night’s rest

Like money, sleep seems most important when we have little of it. And yet, every evening is an invitation to sleep in a way that not only maximizes the 7 to 8 hours of our unconscious lives, but also sets us up for waking to a morning made sweeter and more optimistic by a perfect night’s rest.

As a yogi, I want to wake every day with the energy to get right onto my mat before beginning work. And as a neuroscientist, I have been in touch the field of sleep psychology for many years. Today, these are my evening rituals that create ideal conditions for a peaceful night, every night:

1. Finish evening yoga practice and dinner by 9pm
2. Power down all tech by 10pm; switch out bright lights for candlelight and soft lighting (I use amber lightbulbs in my bedroom)
3. Brew a pot of hot herbal tea, usually chamomile but I change it up with my mood (tea is soothing and also great for digestion)
4. Pull out a sketchbook for drawing, journal for writing, or meditative book for reading. The idea is to creatively process the day’s events so that the mind is at ease for sleeping and sweet dreaming. (No one likes waking up from bad dreams!)
5. Say aloud: Alexa, play ocean sounds; Alexa, sleep timer, 30 minutes.
6. Get into bed when I feel sleepy. My last thoughts of the day are: that was lovely.

To find what will work best for you, let’s explore the foundations of sleep research and then incorporate evolutionary psychology with yogic techniques for you to harness your best night’s potential.

Data-driven advice on how to sleep your best

Before smart phones wove their way into our lives, trouble sleeping was called “insomnia” and sleep research focused on two populations: patients with trouble sleeping, and normal people. Today, normal people have trouble sleeping and people consider themselves “night owls” rather than insomniacs. But after a great night’s sleep, anyone can be a morning person.

Sleep Hygiene

The term sleep hygiene was first used by Dr. Peter Hauri in 1977, to describe the behaviors that increase the measurable quantity and quality of sleep. Based on his clinical observations of patients, Dr. Hauri (Current Concepts; Sleep Disorders; 1977) created these ten rules:

1. Sleep as much as needed to feel refreshed and healthy during the following day, but not more.
2. Keep regular wake times to strengthen circadian cycling and regulate sleep onset.
3. A steady daily amount of exercise will help, but occasional one-shot exercise does not directly influence sleep during the following night.
4. Occasional loud noises disturb sleep even in people who do not awaken. Creating white noise might be advisable.
5. Although an excessively warm room disturbs sleep, there is no evidence that an excessively cold room solidifies sleep.
6. Hunger may disturb sleep. A light bedtime snack seems to help many individuals sleep.
7. An occasional sleeping pill may be of some benefit, but the chronic use of hypnotics is ineffective at most and detrimental in some insomniacs.
8. Caffeine in the evening disturbs sleep, even in persons who do not feel it does.
9. Alcohol helps tense people to fall asleep fast, but the ensuing sleep is then fragmented.
10. Rather than trying harder and harder to fall asleep during a poor night, switching on the light and doing something else may help the individual who feels angry, frustrated, or tense about being unable to sleep.

The field of sleep psychology has continued to work with the concept of sleep hygiene, turning rules and suggestions into diagnostic criteria for poor sleep habits. Created by Drs. David F. Mastin, Jeff Bryson, and Robert Corwyn in 1990, the Sleep Hygiene Index is a self-report questionnaire that is reliably correlated with sleep quality. You can take this quiz yourself, to see if your night behaviors set you up for good rest. Just answer each of these 13 items on a scale of 1 (never) to 5 (always):

1. I take daytime naps lasting two or more hours.
2. I go to bed at different times from day to day.
3. I get out of bed at different times from day to day.
4. I exercise to the point of sweating within one hour of going to bed.
5. I stay in bed longer than I should two or three times a week.
6. I use alcohol, tobacco, or caffeine within four hours of going to bed or after going to bed.
7. I do something that may wake me up before bedtime (for example: play video games, use the internet, or clean).
8. I go to bed feeling stressed, angry, upset, or nervous.
9. I use my bed for things other than sleeping (for example: watch television, read, eat, or study).
10. I sleep on an uncomfortable bed (for example: poor mattress or pillow, too much or not enough blankets).
11. I sleep in an uncomfortable bedroom (for example: too bright, too stuffy, too hot, too cold, or too noisy).
12. I do important work before bedtime (for example: pay bills, schedule, or study).
13. I think, plan, or worry when I am in bed.

Higher valued responses (i.e. frequently engaging in the above behaviors) is a predictor for low quality sleep, so if you identify with any or many of the 13 items above, you may want to examine whether you can alter those habits to improve your rest.

How to sleep, according to the American Sleep Association

Today, the American Sleep Association defines sleep hygiene as “behaviors that one can do to help promote good sleep using behavioral interventions”. Here are their top tips:

1. Maintain a regular sleep routine: Go to bed at the same time. Wake up at the same time. Ideally, your schedule will remain the same (+/- 20 minutes) every night of the week.
2. Avoid naps if possible: When we take naps, it decreases the amount of sleep that we need the next night — which may cause sleep fragmentation and difficulty initiating sleep, and may lead to insomnia and sleep deprivation.
3. Don’t stay in bed awake for more than 5–10 minutes. If you find your mind racing, or worrying about not being able to sleep during the middle of the night, get out of bed, and sit in a chair in the dark. Do your mind racing in the chair until you are sleepy, then return to bed.
4. Don’t watch TV or read in bed: The bed is reserved for two things — sleep and ‘hanky panky’.
5. Drink caffeinated drinks with caution, and only before noon.
6. Avoid inappropriate substances that interfere with sleep: Cigarettes, alcohol, and over-the-counter medications may cause fragmented sleep.
7. Exercise regularly, before 2 pm every day. Avoid rigorous exercise before bedtime. Rigorous exercise circulates endorphins into the body which may cause difficulty initiating sleep.
8. Have a quiet, comfortable bedroom: It should be dark. Turn off bright lights. Set your bedroom thermostat at a comfortable temperature. Generally, a little cooler is better than a little warmer. Turn off the TV and other extraneous noise that may disrupt sleep. Background ‘white noise’ like a fan is OK.
9. If you are a ‘clock watcher’ at night, hide the clock.
10. Have a comfortable pre-bedtime routine: A warm bath, shower, meditation, or quiet time

This list of recommendations is sometimes cheeky (“Hanky panky”?) but founded on scientific studies, taking into account the overwhelming intrusion of data and distraction in our daily lives of 2018.

How do we use these scientific recommendations for our own sleep? Kloss et al (2014) demonstrated that learning about sleep hygiene will improve sleep and reduce maladaptive beliefs about sleep, meaning that simply reading this will help you sleep better.

And though these to-do-lists are simple, the rules can be difficult to follow just because they require perseverance in breaking old habits and dedication to instating new habits. It could be easier to understand how to begin your journey to great rest by understanding the concepts underlying the data-driven recommendations above.

Evolution, Psychology & Yoga

We can divide our best sleep habits into three realms: circadian rhythm, time-management, and mental happiness.

Circadian Rhythm

Humans, like most living species, are hardwired in brain and body to be active by day and rest by night. But unlike other species, we have harnessed the power of fire, electricity, and Instagram, which create invigorating lights and sounds that are not limited to daytime hours.

Part of what signals our bodies to sleep at night is sunset and darkness, when vision (and therefor work) is limited. When we find ourselves in dark, comfortable environments with little to do, our natural response is to sleep. (This is why it feels so good to take a nap while it is raining: the clouds provide a nighttime ambiance and the rain provides soothing white noise.)

So many of the sleep hygiene rules are geared towards recreating this evolutionarily familiar condition of night. To simulate this yourself, consider your bedroom conditions and nighttime habits. Do you automatically turn on bright lights when you get home after work? Do you bring your technology to bed? Do you block out sunlight with blinds and sleep masks while relying on an alarm clock to wake you? These are the sort of habits that feel natural to us today, but also create light and stimuli that keep us awake, while disconnecting us to the biggest element of the circadian rhythm: the sun.

The reason why using technology at night and in the bedroom disrupts our sleep is because on a deep level, we are still animals that are concerned for our personal safety at all times. Evolutionarily, we were most vulnerable when we were sleeping. These hardwired presets still exist, so if we go to sleep under stressful or stimulating conditions today, we instinctively feel the need to stay alert and therefore do not sleep well through the night.

To harness your own circadian rhythm for a peaceful night’s rest, every night, you can create these new habits:

1. Step outside or look out the window throughout the day, noticing the sunlight and sunset
2. Reduce and then avoid caffeine, which resets your circadian rhythm (don’t worry: with time, you will sleep better in the night and naturally reduce your dependency on stimulants. You can try going from espresso to drip to half-caf to black tea to green tea to white tea to herbal tea, a gradual process that worked well for me.)
3. Create a welcoming bedroom environment. Switch out your lightbulbs for soft or amber colored light. Keep all bright lights, loud sounds outside the bedroom. This will teach your mind that the bedroom is a reliably safe and quiet place (both for sleeping, and for hanky panky…).
4. Replace your old bedtime technology routines with activities that do not need to be plugged in. Books and magazines are a happy medium, though they require that your environment is bright enough for reading. It may be best for you to read, stretch, meditate, or write in another room and come to the bedroom only when you are ready to sleep.
5. In the natural world, nighttime is typically cooler than bedtime. You can simulate this at home by lowering the thermostat a couple of degrees in the evenings, and/or taking a hot bath or shower before bedtime. The hot water is relaxing for physical tension and also serves to raise your body temperature so that as you dry and cool off, your body reads the lowering temperature as a signal for nighttime sleep.
6. Have some airflow, plants, and/or white noise in the bedroom, to create a more natural and oxygen rich environment.

Breaking old habits and creating new habits is the most challenging part of creating consistently good sleep, but the effort will be well worth it. You’ll essentially be teaching yourself that the nighttime is time for rest, and the bedroom is a place of perfect peace.

Time Management

Speaking of new habits, the main culprit for sleep deprivation is the inability to let go of technology and unwind in the evening. In today’s over-scheduled lifestyle, there is the pervasive desire to delay bedtime to make more leisure time.

For those of us with demanding daytime responsibilities, we have become accustomed to fending off the inevitable feelings of being tired, bored and annoyed all day. This makes it easy to ignore the feelings of tired and sleepy at night. And yet, it is possible to become more sensitive to your own body’s desire to sleep:

1. Notice when you feel sleepy, versus when you feel fatigued (overworked, or bored). And notice if and when you willfully ignore the sleepy feeling.
2. Consider your ideal sleep and wake times, then schedule your “unwinding” evening time around them. For example, if you would ideally wake at 7:30am, feeling beautifully rested after 8 hours of sleep, then you would need to be peacefully asleep at 11:30pm. To reduce the pressure to fall asleep quickly, perhaps you would ideally be in bed around 11 or 11:15pm. Then you can decide to “unwind” by lowering lights and turning off technology around 10 or 10:15pm, giving you an hour or more of time to relax and enjoy relaxing.
3. Schedule your day accordingly, perhaps even noting that 10pm (for example) is your end point for television, phone calls, social media, and to-do list. Then you can look forward to your time off, and to sleeping, and to waking. After all, the reason that we are interested in a good night’s sleep is that it feels wonderful.

Mental Happiness

Preparing the body for rest is only part of the equation for perfect sleep. It’s possible that we successfully break old habits and create the perfect bedroom environment and take hot baths and turn off technology at 10pm and then get into bed and still can’t sleep, which is an age-old problem better expressed by poets than scientists:

Weary with toil, I haste me to my bed
The dear repose for limbs with travel tired;
But then begins a journey in my head
To work my mind… (Shakespeare; Sonnet 27)

Here are some ways to create mental health and clarity in the time you set aside to relax yourself for a great night’s rest:

1. After powering down your technology, and/or after your hot bath or shower, find a quiet place to stretch out your body. Do anything that feels good, for however long you like (even five minutes will feel great.) When you finish, sit with your spine straight, eyes open or closed, and listen to your breath. Notice the pace of your inhale, and the pace of your exhale. When you find yourself thinking instead of listening, just come back to the breath.
2. If you find yourself busy thinking important thoughts, write them down. It can be helpful to keep a notebook dedicated to your evening thoughts, or it can be helpful to throw away what you have written. The purpose is to anchor the thoughts on paper; it doesn’t matter if you or anyone else reads it later.
3. Pick up (or dust off) an artistic hobby. You don’t have to be a talented or inspired artist to enjoy the benefits of sketching, gardening, or playing an instrument. All of these hobbies will allow you to express yourself creatively, channeling your thoughts and feelings in a constructive way before you lay down to sleep.
4. If you are in bed and wanting but unable to fall asleep, lay on your back with your eyes closed. Listen to yourself breathing as you feel your belly rise and fall. Then take your attention into your feet. Feel, with your mind, your feet, then work your way up to your legs, your pelvis, your abdomen, etc., feeling your whole body from the inside. If you get distracted by your thoughts, return to your breath then back into your body.

Allowing yourself to integrate your mind and your body, while releasing the day’s thoughts and events, will create the peaceful conditions ideal for a perfect night’s rest. You’ll rest easy, enjoy sweet dreams, and wake feeling bright and reenergized for a new day.

In Summary

The true take home message here is that our bodies and minds need and love rest. All we have to do is attune our minds to our most fundamental needs, and trust our bodies to do the rest.

Inspired to Rest