If you are serious about your training, you may want to invest in a sport watch. It has a built-in sleep tracker so you can measure your sleep quality.
From Sigma Sports
Garmin Forerunner 965 GPS Watch - Black/Grey
The product is available from £473.81 at international stores.
365rider
Garmin Forerunner 965 Black Grey
This product is also available at 1 unverified merchant.