For an entire academic year during college, while I was going through a neurotic self-improvement phase, I kept a sleep log. I recorded when I slept, when I woke, how long that period was, a sleep quality rating 1-5, and a brief note explaining context. It was one of the first things I did each morning.

Date Sleep Wake Hours Rating Note
Aug 29 12:25 AM 7:30 AM 7:05 3 Woke up very thirsty
Aug 30 12:15 AM 8:10 AM 7:55 4 Fell asleep reading
... ... ... ... ... ...

Here are the results: On average, I slept at 12:45 AM, woke at 7:55 AM, got 7:10 hours of sleep, and had an average rating of 3.15. I only rated a single night as 1 (worst sleep ever) and none as 5 (best sleep ever). The main factor affecting my sleep quality rating seemed to be the length of sleep, though my sleep and wake times were fairly consistent. My 1 rating sleep length was for 5:00 hours, 2 rating sleeps were on average 6:44 hours, 3 rating sleeps 7:11 hours, and 4 rating sleeps 7:21 hours.

I would read later that research has established human sleep cycles as being approximately 90 minutes in length; waking up at the completion of a cycle can maximize both waking restfulness and perception of sleep quality. Many sleep improvement gadgets rely on this one factor for their success. The results from tracking my own sleep metrics seem to conform to this theory. It could always be a placebo effect, but it works for me.

PS: <div align="center">Fitbit Flex</div>

I got a Fitbit Flex last month that has greatly improved how I track my sleep. I’ll write a post with the results and a quick review when I get enough data. In the meantime, I have zero friends on it so give a shout if you have one too!