According to research presented at the European Society of Cardiology Congress , taking an afternoon nap can lower blood pressure. The study included 386 people aged 61 on average and all with raised blood pressure. After adjusting for other factors, the study found that nappers had a four per cent lower blood pressure reading when awake and a six per cent lower reading while asleep than participants who didn't nap. While the reduction may seem small, researchers added that even small reductions have been found to reduce the chance of cardiovascular events by up to 10 per cent.
Each sleep stage in any particular sleep cycle fulfills a distinct physiological and neurological function, each of which appears to be necessary for the health of the body and mind, to the extent that, if sleep is interrupted or if certain stages are missing for any reason, their physiological functions are not fully executed, and the person may feel tired or groggy even after an apparently sufficient sleep period , a phenomenon known as “ sleep inertia ”. In recent years, special alarm clocks have become available which purport to monitor a person’s sleep stages and cycles and only wake them during periods of light sleep , when the deleterious effects of this sleep inertia are least acute.