In the last blog, I discussed several benefits of getting more sleep, including improved metabolic health, cognition, and athletic performance, not to mention protection against the effects of future sleep loss. But how can you sleep longer?
In this blog we’ll focus on this question. Extending your sleep can seem tricky, but sleep extension often is feasible. And even if you can’t sleep longer for several nights at a time, you may still benefit from being opportunistic and banking sleep when you can.
Sleep longer, for very few people don’t need much sleep
First, understand that the odds that you need less than 6.5 hours of sleep each night are exceptionally small. A very small minority of people have variants of genes that both buffer these people against the perilous consequences of sleep loss and also reduce how much sleep they need (1). This blog is less relevant to these people. But you probably aren’t one of them. Sorry! So, let’s now look at factors that hamper your ability to sleep longer through their influence on biology.
Sleep longer by reducing your caffeine intake
Caffeine is the most-consumed psychoactive drug globally and can restrict sleep.
The longer someone has been awake, the greater the accumulation of certain products of metabolic reactions in the extracellular fluid surrounding brain cells. Some of these products promote sleep (especially deep sleep), foremost among which is adenosine, a nucleoside that binds to adenosine receptors in brain circuits involved in sleep regulation. As an adenosine receptor antagonist, caffeine blocks the interaction of adenosine with its receptors, reducing the sleep-promoting effects of adenosine (2).
After consuming a modest amount of caffeine, it takes healthy people about six hours for their blood caffeine levels to fall to 50% of peak values, on average. This time varies depends on many factors (including caffeine dose, diet, liver function, and time of day) and varies greatly between people though (3). And because caffeine remains in the body for many hours after ingestion, it may shorten time spent in deep sleep, even when consumed as long as six hours before bed (4). Keep in mind that the greater the dose, the longer caffeine will remain in your body.
Reducing caffeine intake therefore helps most people sleep longer, and the only way to find out if you will benefit from curbing your consumption is to give it a go. You can go about this in one of two ways. One option is weaning yourself off caffeinated products like coffee, tea, “energy” drinks, and chocolate (see this website to find out which items contain caffeine). The alternative is to cut your consumption of all caffeine-containing items to your target level immediately.
Some of you may prefer to temporarily cut all caffeine from your diet. Personally, I feel I sleep best when I consume no caffeine whatsoever, but this is just one person’s anecdote, and you should experiment to find what suits you best. However, I’ll add that habitual caffeine use leads to tolerance, so if you temporarily stop consuming caffeine entirely then you’ll resensitize your body to its beneficial effects when you reintroduce it.
If you choose to still consume some caffeine, I generally recommend beginning with the following rule of thumb: consume no more than about 1 mg caffeine per pound of bodyweight (2 mg per kilogram) no later than nine hours before your regular bedtime. So that might be no more than an 8 fl oz cup of brewed coffee before 13:00 for a 170 lb man who goes to bed at 22:00, for example.
Heavy caffeine users may initially suffer short-lived caffeine withdrawal effects, such as listlessness and headaches. But hang in there and your sleep may improve dramatically! Needless to say, use of other stimulants routinely impairs sleep too.
Sleep longer by reducing your alcohol intake
As is true of stimulants, alcohol impairs sleep. While alcohol consumption often reduces how long people take to fall asleep, it typically disrupts sleep later in the night (5). Alcohol also tends to alter sleep structure such that people spend more time in deep sleep, especially early in the night, and less time in rapid eye movement sleep (the stage in which you dream). Now, all stages of sleep are important, for each serves unique and critical roles – we don’t want to interfere with sleep architecture. And you probably know that you’re more likely to snore (alcohol is a muscle relaxant) and visit the bathroom at night after drinking alcohol. So, you might want to think about backing off the booze for a bit.
It is again tricky to give precise recommendations regarding alcohol and sleep for there is much variation between people in how they metabolize alcohol. This said, people tend to clear alcohol from the blood at a rate of about 20 mg/dl/hour (6). So, as another heuristic, you may want to limit yourself to two units of alcohol each day (see this website to find out how much alcohol you’re consuming). And as is true of caffeine, shifting your intake earlier may also reduce how much any alcohol that you consume interferes with your sleep, so try to consume alcohol no later than four hours before your regular bedtime.
A huge number of other dietary constituents influences sleep, so we won’t consider more here. I will, however, add one more concept: consuming Calorie-containing items very close to bedtime may disrupt sleep (7). This could be for several reasons, one of which is that digesting and metabolizing nutrients increases core body temperature. As I discussed in a previous blog, core body temperature wanes during sleep, and this aids sleep onset. Late Calorie intake may therefore increase core body temperature and hence hamper sleep initiation.
Last, one tip applies to behavior change writ large: make things easy for yourself by reducing temptations. If possible, give away items containing alcohol and caffeine. If you live with other alcohol and caffeine consumers, can you get them to join you in your quest for super sleep? The support and accountability of peers can greatly boost the probability of you achieving your goals. You can even use guilt to aid your efforts, perhaps trying accountability apps like StickK to keep you focused.
Sleep longer by changing your light exposure to shift your sleep timing
Another strategy to get more sleep is to shift your sleep onset earlier, but just going to bed earlier is often ineffective. The reason is that your circadian system (the biological clock that programs your daily patterns of biology and behavior) regulates your sleep timing, and there is a “forbidden zone” for sleep shortly before your circadian system permits sleep. This is because your circadian system produces a strong drive for wakefulness late in your waking day, so trying to sleep at this time is generally a fool’s errand.
Now, the main cue that sets the timing of your circadian system is light exposure. And this is critical: To shift your circadian system earlier, expose yourself to more bright, blue light early in the day and less at night. Doing so will be especially helpful in falling asleep earlier.
A simple approach is to spend more time outside early in the day and to reduce your exposure to artificial light at night. Apps like f.lux filter blue light from devices like computers at night and can be handy if you must spend time in front of screens late in your day. You may also benefit from reducing the brightness settings on these devices. Last, if you’re not the self-conscious type, wearing blue-blocking glasses at night can be another useful strategy.
My upcoming course on the circadian system addresses these concepts in far more detail, so watch this space!
Sleep longer by setting an alarm for bedtime
Here’s a tip that many people find transformative: set an alarm for bedtime.
About 80% of us use alarms to prematurely, jarringly, and lamentably halt sleep (8). And often this is just from going to bed late – watching another program episode on Netflix is sometimes too alluring, right?
But what if we trained ourselves to adopt better pre-sleep routines, like having a warm shower, reading a book in dim lighting, and shutting down when the clock strikes sleep time? We’d sleep better, of course. And we might reduce the frequency with which that dysphonic alarm ringtone pollutes the peace of the morning.
So, set an alarm for the time at which you plan to begin your pre-bed routine. How long before bed this needs to be depends on your habits. Perhaps you brush your teeth, shower, and spend half an hour reading in bed before you sleep. In this case the alarm would be set for about 45 minutes before bed. If I had to give a general recommendation, I’d advise that you set an alarm for an hour before when you plan to sleep.
If you must use a morning alarm, you’ll want to set it to go off as late as your schedule allows. Don’t be one of those people who sets four alarms, the first of which goes off an hour before it’s actually time to get out of bed! Fortunately, we needn’t set any alarms to wake on non-work days, so do sleep in, especially if you’ve lost sleep in the preceding days or are liable to forego sleep in the coming ones.
A final piece of this puzzle is knowledge of your behaviors. This is where humanOS comes in. You may benefit remarkably from using humanOS to track your sleep. And you don’t need a device like a FitBit if you don’t have one – you can enter your sleep times manually if you like. Pay close attention to your bedtimes in the sleep tile on humanOS, as tracking your bedtimes may help you consolidate your pre-bed routine. Here is a short video showing you how to track sleep using humanos:
Sleep longer… whenever society permits you to!
And now we come to societal factors that curtail our sleep. These include work and school times, and the latter perfectly exemplify the benefits of getting more sleep. A recent study used macroeconomic mathematical modelling to forecast the results of delaying school start times in the US.
Not only would the number of kids graduating from high school increase, but the number of adolescent car crashes would fall considerably. Oh yeah, the US economy would also gain an $83 billion surplus after a decade (9).
Adults would benefit from more flexible working hours that are tailored to our chronotypes (the individual propensity that makes some of us “morning larks” and others “night owls”). Recent research has shown that workers enjoy improved sleep when shift work schedules are tailored to people’s chronotypes (10), but ultimately the buck stops with the people who make decisions about working hours. There are many instances of people being nudged into making healthier choices and smarter decisions without even realizing it. (You’d be more likely to reach for fruit and vegetables if they’re placed at the start of the canteen, right?) There’s no reason people can’t also be coaxed into sleeping more, but work schedules might need changing for this to happen.
In these two blogs, we’ve explored the many benefits of sleep extension, as well as some practices you can try to sleep more yourself.
The crux of the matter comes down to this question:
Would you prefer to 1) spend slightly more time awake but feel and perform worse, or 2) sleep a little longer in exchange for improved health and productivity?
I know my preference.
To sleep longer:
- Reduce your stimulant and alcohol consumption, as well as your intake of Calorie-containing items shortly before sleep.
- Expose yourself to more bright, blue light early in your day and less light shortly before bed to help you sleep earlier.
- Set an alarm for bedtime.
- Use humanOS to track your sleep.
The graphic below summarizes key points that we’ve reviewed in these two blogs:
- He Y, Jones CR, Fujiki N, Xu Y, Guo B, Holder JL, Jr., et al. The transcriptional repressor DEC2 regulates sleep length in mammals. Science. 2009;325(5942):866-70.
- Porkka-Heiskanen T. Methylxanthines and sleep. Handb Exp Pharmacol. 2011(200):331-48.
- Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. Alcohol and sleep I: effects on normal sleep. Alcohol Clin Exp Res. 2013;37(4):539-49.
- Gershman H, Steeper J. Rate of clearance of ethanol from the blood of intoxicated patients in the emergency department. J Emerg Med. 1991;9(5):307-11.
- McHill AW, Phillips AJ, Czeisler CA, Keating L, Yee K, Barger LK, et al. Later circadian timing of food intake is associated with increased body fat. Am J Clin Nutr. 2017;106(5):1213-9.
- Roenneberg T, Allebrandt KV, Merrow M, Vetter C. Social jetlag and obesity. Curr Biol. 2012;22(10):939-43.
- Hafner M, Stepanek M, Troxel WM. The economic implications of later school start times in the United States. Sleep Health. 2017;3(6):451-7.
- Vetter C, Fischer D, Matera JL, Roenneberg T. Aligning work and circadian time in shift workers improves sleep and reduces circadian disruption. Curr Biol. 2015;25(7):907-11.