Sleep more, perform better

These are the facts. One, your performance decreases the more sleep deprived you are. Two, your learning is hampered if you don't sleep well.

For those unaware of how sleep debt works, here's a short, simplified explanation. First, everyone has pretty much a fixed daily sleep need. This sleep need varies individually: some need only five hours of sleep per day, some people need nine, most fall somewhere in between. When you sleep more than your daily sleep need, your sleep debt is decreased and vice versa when you sleep less than your daily sleep need. The more sleep debt you have, the more tired you feel.

This tiredness is somewhat masked by circadian alerting and external stimuli. Circadian alerting is a biological process, which makes you more alert starting in the morning and starts to make you really drowsy in the evening. External stimuli are things like caffeine and states of mind like being excited. Below is a picture that graphs your sleep urge during different times of the day. (Think of "sleep urge" as the reverse of alerting.)

Now, this system of sleep debt is automatic. Just like a thermostat controlling the temperature of a room, your brain just starts to make you more sleepy when you gain sleep debt and more alert when you decrease it. You can't consciously decide to sleep less. Eventually the sleep urge becomes so over-whelming that you can't fight it anymore. If you've ever seen those documents about people who have tried to stay awake for as long as possible, you know what I'm talking about. After a couple of days of being awake, they start to grow more and more tired. (Though in fact these people who stay awake for long periods start to develop microsleeps in which the they fall asleep for just couple of seconds every now and then. Typically they can't even notice these sleeps by themselves.) The research in sleep deprivation shows that this same happens even if you miss just half an hour sleep per day: it just takes a lot longer to become so sleep deprived that you start to fall asleep during the day.

The jury is still out whether this sleep debt system is in fact one-to-one between the amount of sleep that you've lost and the amount you sleep more later. That is, whether your daily sleep amount converges with your sleep need in the long run. The evidence suggest that this is the case. So you can't decide to sleep less, because your natural sleep urge just makes you sleep more later.

But for the serious student of pool, or any other discipline for that matter, the lesson isn't about whether or not you can sleep less. The serious student should make it a priority to sleep as much as possible.


Whether or not you can "cheat" the system by constantly sleeping less, the fact remains that your performance increases in all aspects when you constantly sleep as much as you can. Veteran sleep researcher William Dement describes this in his Google Personal Growth series talk. Dement shows graphs from studies in which Stanford athlete students are put to sleep extension programs and after couple of weeks of sleeping as much as they can, they start to perform better in all aspects of their discipline. They run faster, they shoot baskets more accurately, they jump longer and so on. It's pretty amazing if you think of it: these are people who aim to be professionals in their discipline and their performance increases just by sleeping more. They thought that they knew how good they were, but after a couple of weeks of extensive sleep, they performed better.

But there is even more to it.

Recent research also suggests that sufficient sleep is necessary for efficient learning. If you practice a fine motor task, like for example pocketing balls with a stick, you have to sleep during the next night or else the practice is completely forgotten. In fact, your fine-motor control is refined during the sleep. You learn during the sleep! The better you sleep at night, the better you learn. If you don't sleep next night after a practice, you don't learn anything. Matt Walker describes this line of research in his Fora.tv talk.

How do you make sure that you get enough sleep?


If you've taken seriously what I've said, you might be wondering whether or not you are sleeping enough. The short answer is that if you don't feel tired during day-time, you are getting enough sleep. If you do feel tired say one hour after waking up in the morning, you are probably sleep deprived. Note though that there is a dip in alertness in the afternoon, which you can see in the graph above. So even if you are sleeping enough, you might still experience afternoon drowsiness and this is just because there's a dip in circadian alerting. But all in all, the best indicator of sleeping enough is your day-time alertness.

If you are sleep deprived, however, the correction is simple: start sleeping more. The research has shown that you can't sleep too much, contrary to the popular belief. If you just sleep as much as you can, eventually your sleep debt decreases to zero and you start feeling less and less tired. (And you start perform better, as discussed earlier.) But you can't sleep away your whole sleep debt in one go. Even if you're extremely sleep deprived, eventually the circadian alerting kicks in and you wake up.

The best way to make sure that you get enough sleep in the long term is to set up a fixed time to go to sleep, say 10 p.m. in the evening and to sleep as long as you can in the morning. There's some flexibility to the exact time you can go to sleep, but not much, maybe an hour or so. This type of arrangement ensures that you are able to fall asleep predictably. If your sleep schedule is chaotic, you might not be able to fall asleep even if you're extremely sleep deprived. Yes, this means that you shouldn't be pulling those all-nighters at the pool hall.


In summary: if you want the best performance out of yourself, you should stick to a fixed sleep schedule and sleep as much as you can. 


(You need to avoid alcohol too, because it decreases the quality of your sleep significantly.)