Along with exercise and nutrition, sleep is one of the primary determinants of your happiness and wellbeing. If you don't get good sleep, you will not only be tired, but also pessimistic, unmotivated, lazy or even depressed.

Research has shown that self control is a limited resource that is greatly diminished when you're exhausted. If you don't get good sleep, you are less likely to be productive and stick to your good habits (such as exercise). You are also more likely to do things that you know are bad for you (such as eating sweets).

Good REM sleep plays a critical role in the development of long term memories. If you're trying to learn anything at all, you better make sure you get enough high quality sleep.

Proper sleep is also essential for maintaining a robust immune system. If you want to be happy, healthy, smart and productive, you have must make sure you get good sleep.

Do you think that your physical health and emotional wellbeing can be considered in isolation? Think again. They both come from the same body, and they both require that you sleep well.

In marketing they say that you can't improve what you don't measure, and the same is true for sleep. If you track your sleep, you will always know how good it was, why it was like that, and what needs to be done to improve it.

How can you track your sleep?

It's simple. All you have to do is take your smartphone to bed with you and use a special app such as Sleep Cycle for iPhone. There are similar apps available on other platforms as well.

In addition to tracking your sleep, these apps analyze your movements and use that information to wake you up when you're most awake in a given time interval. This feature actually makes it a lot easier to wake up, and you even hate your alarm less.

At the end of each night, you'll see the time you went to bed, fell asleep, woke up, and what sleep phases you've been through that night. Over time, you'll also see your average statistics and how your sleep patterns have changed.

To make sure that your phone doesn't bother you while you're sleeping, always turn on airplane mode. That should eliminate any (possibly) harmful radiation as well.

What I Have Learned About Sleep

When you wake up, the two coolest things you see in Sleep Cycle are the time you fell asleep and sleep quality score, which is based on time spent sleeping and the phases you've been through.

In and ideal world I would fall asleep the moment I go to bed, but that's rarely the case. It turns out that just one cup of coffee at any time after 5 PM makes it a lot harder for me to fall asleep. I have since given up coffee after 5 PM.

Similarly, just one or two beers in the evening will reduce my sleep quality to the extent that I wake up feeling significantly worse. I couldn't call it a hangover because I've had so little alcohol, but I feel significantly worse than I normally do. So no casual beer in the evenings. It's not worth it.

Regular exercise has helped me greatly improve my sleep quality and energy levels. It becomes a lot harder to fall a sleep if I haven't worked out for a few days. However, if I'm really tired from working out, it can be hard to fall asleep as well.

If you want to sleep well, you must go to bed at more or less the same time every night. It doesn't really matter when that is, just choose something that fits your schedule. I try to go to bed between 1 AM and 2 AM every night. You can't be an early person if you're living in a noisy dormitory.

I usually have problems with sleep if I get off my schedule because of a party or some other reason. The next day it's a lot harder to get anything done. That's why I try to stay consistent with the time I go to bed.

Finally, emotions can also affect your sleep quality a lot. In general, stress and anxiety (positive or negative) both reduce my sleep quality and make it harder to fall asleep. The recent low point in the graph bellow corresponds to the time I lost my job. Huge impact as you can see.

Everyone's sleep patterns are a little different, so I encourage you to start tracking on your own to see what works for you.

Changing Sleep Patters

While most people don't get enough sleep, I've had the opposite problem for most of my life. I was the kind of guy who could sleep for 11 hours on any given day and still wake up tired. I never had the time to do anything. I was always sleeping.

Needless to say, I didn't get much value from the last two or three hours every night. Even worse, I often already felt tired when I woke up, yet I struggled to fall asleep at night.

Last year I realized that it had to be changed. I started to limit my sleep to nine hours on any given night. Eight hours are probably optimal for most people, but since I was such a heavy sleeper, I thought that nine hours might work better for me.

I was really strict on myself, and for weeks I never broke the 9-hour rule. At first it was very hard. I was really tired for most of the day, but I knew I had to keep trying. I didn't want to spend 46% of my life in bed any more.

After a few weeks I realized that I was actually full of energy even though I had slept less than nine hours that night. I no longer needed ten or more hours every night. This may sound a little weird, but it was a huge win for me.

My first success inspired me to test if I could further improve my sleep patterns. I soon discovered that it was better to focus on the time I spend in bed, not on the time I spend asleep.

I have complete control over when I go to bed and when I get out of it. But when I fall asleep is something that I can't control. I used to change my alarm for later and later when I couldn't fall asleep straight away. I would get anxious about not getting enough sleep and feeling tired the following day... which made it even harder to fall asleep.

Such thoughts lead to a lot of unrest, so I decided to focus on the hours I spend in bed instead. Now I don't care how long I sleep at night as long as I spend a set number of hours in bed.

This system also introduces a self-correcting mechanism to my schedule. If one night I can't fall asleep for a while, I sleep less, and it becomes easier to fall asleep the following night.

How much time should you spend in bed?

You should try to have enough energy throughout the day while keeping it easy for you to fall asleep at night. You can only find out how much that is through testing. Pick any reasonable number (say 8 hours), stick with it for a couple of weeks, and then adjust if needed.

Recently I've been setting my Sleep Cycle alarm 8.5 to 9 hours after I go to bed. If I do 8.5 hours, I get about 8 hours of sleep. It takes me about 15 minutes to fall asleep, and the alarm goes off 0 to 30 minutes before the time I specify.

Setting my alarm after 8.5 hours was perfect until I started working out four times a week. I would get really tired, so I had to switch to 9 hours. Even though I now lose half an hour, I can be a lot more productive in the other 15 hours of the day.

Finally, I really recommend that you get out of bed as soon as you first hear the alarm. Forget about snoozing. This is easier said than done, but there is really no point of staying in your bed when you're already awake. Just get out.

If you have trouble hearing the alarm, try changing the tone more often. Sleep Cycle has a random alarm function, so every morning I am surprised by a fresh (and really weird) tune.

Congratulations if you actually got this far. That means you take sleep seriously. What are your main tricks for improving the quality of your sleep? Is there anything you would do differently?

Please let me know in the comments.