Optimizing Sleep
INTRO
It’s now reported that about 50% of adults in the US report unsatisfactory sleep. This guide will discuss ways to optimize sleep, and increase sleep satisfaction and next-day functioning.
PRINCIPLES
There are five main categories for sleep optimization:
(01) Time in Bed
Plan to get enough time in bed for complete sleep, which means getting all the sleep your body wants to naturally get. Let’s say you want to sleep seven and a half hours a night. Well, you’re not going to meet that goal if you’re only in bed for six hours. Plan for enough time in bed.
(02) Consistent Bedtime
Going to bed close to the same time every night is an independent determinant of good sleep. In other words, your satisfaction with sleep is not just dependent on how much sleep you get but also when the sleep takes place. Going to bed at the same time every night helps optimize sleep by regularizing the phase of time in which your sleep occurs. Sleeping outside of this phase will make the sleep itself less effective no matter how much sleep you get.
(03) Daytime Exposures
Daytime activities strongly affect how well you sleep at night. Every second you are awake, chemicals that promote sleep accumulate in your brain. The rate at which these accumulate is partly dependent on whether you were mentally and physically active enough in your day. Daytime natural light exposure - and optimized indoor light - are also key.
(04) Pre-bed Routines
There are a variety of things you can do to prepare the body and mind to get to sleep more quickly and to sleep more deeply.
(05) Sleep Environment
Most intuitive for good sleep is creating an environment that doesn’t interfere with sleep itself. This includes factors like light, temperature, sound, and comfort.
TIME IN BED
To get the benefits of good sleep, you must give yourself enough time in bed to get all the sleep you need.
Tracking
To help you stay mindful of your time in bed from night to night, use a sleep tracker. There are many ways to track sleep but we encourage you to use the humanOS sleep tracking tool as it helps you focus on the most useful metrics (not the most metrics, like some tracking systems). Do you know what’s also key here? Setting a goal. A big part of why tracking is useful is because the process (should) help you set a goal for how much sleep you’re trying to get. This process by itself helps you consider your sleep more deeply. Tracking then helps monitor how you’re performing against your goals and helps you stay engaged in trying to get your best sleep on a daily basis.
Avoid Alarms
When possible, avoid waking to an alarm to allow your body as much sleep as it wants.
Sleep Period vs Sleep Time: Know the Difference!
As far as John was concerned, he was asleep the whole time. Again, this is normal and hence the difference between sleep period and actual sleep time. Humans typically self report sleep period when thinking about sleep time. Furthermore, things get rightfully confusing for people when, for instance, they get a sleep tracker and it tells them they got six and a half hours of sleep last night. But John thought he needs eight hours of sleep because that is what is recommended by the National Sleep Foundation!
When you hear that humans need 7-9 hours of sleep per night by an expert organization like the National Sleep Foundation, just note that they are reporting these numbers based on how people report sleep, not off of clinical sleep time calculations. So, the main point is to aim to find your sleep period when is very likely somewhere between seven and nine hours per night for full, complete sleep.
BEDTIME
Bedtime Goal
What gets measured gets managed. These days our sleep patterns are in competitive warfare with really appealing entertainment devices that want our attention. Autoplay yet another episode on Netflix anyone? If you don’t have a bedtime goal, it’s easier to say yes to temptations that rob you of, let’s say, 20 to 40 minutes of sleep each night. Over a week, that adds up.
DAYTIME EXPOSURES
Daytime Light
Yes, daytime light actually helps you get better sleep at night. And, we’re not getting that much outdoor light these days. So, aim to get at least 10 minutes of outdoor light before 10a (or within the first three hours of waking) and at least 30 minutes of outdoor light each and every day. See our How-to Guide on Smart Daily Light for more information.
Physical Activity
Between the hours of when you wake up and when you go to bed, as compared to being very sedentary, getting physical activity can help you get better sleep. In general, follow our physical activity recommendations from our course How Much Exercise Do We Need - which are approximately based on the US government guidelines for physical activity. While there is a lot of flexibility in how you can achieve these weekly guidelines, for our purposes here, also consider getting at least 30 minutes of physical activity per day. This includes anything from going for a walk to activities that are more intense. Note that exercising excessively, relative to your average level of activity, can worsen sleep, so be sensible about how much activity you plan on getting on a given day. Also, aim to finish strenuous exercise at least three hours before bedtime. High-intensity exercise – such as interval training, sprinting, and resistance training – results in many short-lived changes in our bodies that can disrupt sleep.
Mental Work
Tasks that require concentration actually help your sleep and brain health in general. Note that some of these challenging mental activities can be relaxing too, such as meditation.
Naps - What You Need to Know
When you nap, the concentrations of sleep-promoting chemicals in your brain decline. This may make it harder to fall asleep at night and reduce the depth of your overnight sleep, especially if you aren’t used to napping. Naps can be healthy and helpful, just use napping judiciously!
- Timing: While a nap can occur at any time during a 24 hour day, the most common time for naps occur between the hours of 2-4pm in the afternoon. Why? It is this time in the day where there is a natural decline in wake drive - one of the factors that influences arousal across a 24 hour period. After this window, wake drive picks back up in it’s activity which is often why it’s hard to nap if you miss this window.
- Power Naps: These naps are about 20 minutes in length. They allow enough time to nod off in that window but they prevent sleeping long enough to get into deeper stages of sleep. Short naps can be remarkably restorative, improving elements of cognition for the remainder of the day.
Longer Naps
Longer naps have their place but there are some reasons to avoid them. A good long nap can be a great way to reduce excess sleep pressure if you haven’t been getting enough sleep. The two main risks for longer daytime naps is 1) you wake up in a deeper stage of sleep from your nap and then feel groggy for the rest of the day, and 2) you sleep long enough to reduce sleep pressure, which makes it harder for you to fall asleep and stay asleep in the coming night.
PRE-BEDTIME ROUTINE
This section includes strategies you do in the evening to prepare for the best sleep possible.
Modify Evening Light
See our How-to Guide for Smart Daily Light for more details about this important factor for superb sleep. Briefly, excessive exposure to intense (enough), full spectrum white light in the hours before bedtime increases alertness and delays sleep. In the evening, especially starting two hours before your goal bedtime, mitigate the negative consequences of artificial light on sleep by:
- Dimming light intensity
- Filtering blue light entering your eyes
Bedtime Alarm
Set a smartphone alarm for 60-minutes before your target bedtime. Have this alarm automatically repeat every night. Do this so you can give yourself a warming to start winding down your activities and also to start your pre-bed routine.
Set your alarm for 9:00 PM if you plan to go to bed at 10 PM.
Get into Sleep Mode
In our hyper-connected, 24/7 societies, we need discipline to unwind at the end of the day, and this is made easier by ingraining a smart pre-bedtime routine.
Avoid stressful activities in the two hours before bedtime.
Different people find different things stressful, so we can’t be too specific on what you must avoid. Examples of activities many people find stressful include being with certain people, having difficult conversations, reading the news, checking work emails, checking financial portfolios, and watching unnerving TV programs (such as horror films).
Make a To-Do List.
Spending five minutes writing a to-do list for the next few days helps some people calm their minds and fall asleep faster. Do this within an hour of bedtime.
Last 30 Minutes Before Sleep
Do something relaxing in the 30 minutes before bedtime. This might entail reading a novel in dim lighting, for example. Alternatively, you might find that meditating at this time helps you unwind. (Try a body scan meditation, such as one of these:
Hot showers or baths
For 10 mins at ~104 °F (40 °C) within an hour before bedtime. This will increase the temperature of your skin. Doing so helps your body radiate heat out from its core, which is key to falling asleep quickly.
Red in Bed
For light in bed before sleep, use the mnemonic ‘red in bed’. Red and amber toned light enables you to see perfectly fine but it doesn’t tell your circadian system that it is daytime (which keeps you up by masking your sleepiness and leading to under-performance the next day).