What is the impact of alcohol on sleep? It is known that alcohol reduces the quality of sleep- in part by action on heart rate. Alcohol increases sympathetic activity and decreases parasympathetic activity.

Here is my own data from the Microsoft band. During sleep the band measures my heart rate for 1 minute in every 10. It uses variability in heart rate to decide if I'm in light or deep sleep.

Usually my heart rate falls during sleep. Last Friday night I slept over 9 hours (!) and my heart rate fell to 53bpm. I hadn't had any alcohol for probably a week at that stage. The next night I was at a party where I had a few glasses of wine. Both nights my heart rate on getting into bed is about 75bpm but on the night I drink alcohol it increases when I go to bed! It never falls below this level and in fact rises to about 90bpm at times.

I'm not sure what else I will learn through the MS Band but this is certainly an 'actionable insight'. Don't drink alcohol if you want to sleep well!