Although many people have extolled the virtues of day-time naps (not to mention siestas) including famously Winston Churchill, experts are now suggesting that people who do so are at greater risk of developing heart disease and diabetes.
Feeling sleepy in the day may be a warning of metabolic syndrome,a cluster of conditions such as high blood pressure, high cholesterol, excess fat round the waist, and high blood sugar.
This condition is thought to affect 15 million people in the UK who are at risk of developing more serious conditions and having a sleep for 40 minutes during the day increases the risk and if you sleep for 90 minutes the risk increases by 50% according to research by Dr Tomohide Yamada at the University of Tokyo.
The research supports guidelines from the National Sleep Foundation that naps of 20-30 minutes increase alertness.
I remember reading somewhere (and probably posting it at some time) that the trick to having a power nap was to have a cup of coffee before you started it. The caffeine takes about 20 minutes to have an effect on you so when you wake up it kicks in and you’re ready to go!