As different types of sleep sensors grow in popularity, The Guardian examines if they actually do users any good.

For some users, that curiosity can lead them to understand how to sleep better. “My Fitbit told me I slept for more hours than I thought I did,” said James Stockton, 29 from Southampton. “It was quite encouraging, and I could see patterns in my sleep when I exercised more or drank alcohol.”

If, however, inspired by a sleep gadget, you want to find out general tips for better sleep, you will discover the advice doesn’t fit so well with a modern lifestyle. Screens on smartphones, tablets and TVs emit blue light that disrupts the natural process of falling asleep – and is best avoided for an hour before going to bed. Avoiding alcohol and caffeine raises the quality of sleep, as does getting regular exercise.

Motion trackers aren’t the only gadgets claiming to track sleep. Products such as the SleepRate, which comes with a chest strap, will track heart rate, which can be used to infer sleep. Although more accurate than motion trackers, they still cannot conclusively monitor all stages of sleep and reveal the crucial quality of a period of sleep.