The Fitbit Charge HR allows one to track their sleep by continuously monitoring motion and heart rate. It uses algorithms to infer when its user falls asleep and when they wake. The next morning, Fitbit's software can generate a report of the sleep, including:
- Time spent asleep
- Sleep/wake schedule (timestamps for "bedtime" and "wake up")
- Periods of wakefulness (plus number of times awake and total time being awake)
- Periods of restlessness (plus number of times restless and total time being restless)
How can I use this report to gauge the quality of my sleep? What's normal, and what's the ideal?
A naive answer might be that 8 hrs of sleep plus no periods of restlessness or wakefulness would be ideal. This varies from person to person and with age, however: a baby wakes more than an adult, and an elderly person may wake to use the bathroom--but each case is healthy and "normal". Moreover, a sleep doctor I had once said that it's normal and healthy for the body to turn over several times while sleeping, if only to improve circulation and decrease stiffness.