Those not sleeping enough or well have one more reason to worry. Sleeping for less than six hours or waking up more than two to three times at night raises your risk of heart attack and stroke threefold, reports the first review of sleep quality and duration in India."A couple of sleepless nights or a short spell of insomnia are okay, but chronic sleeping problems — sleeplessness or truncated sleep for two weeks or more — can cause problems as varied as difficulty in concentrating to hypertension, heart disease, obesity, mood disorders and frequent infections," says Dr JPS Sawhney, head of cardiology at Ganga Ram, who co-authored the study. Some studies have also linked insomnia with cancers and insulin resistance, which is a precursor of type-2 diabetes.
The study, done at Ganga Ram Hospital and reported in the Indian Heart Journal, reviewed the sleeping patterns of 352 people aged 18 years and more and found both insomnia and poor sleep quality were risk factors for heart attack and stroke, independent of established risks such as obesity, high blood pressure, smoking or high cholesterol.
"Getting up with morning headaches, feeling tired or fatigued after a night's sleep, getting up more than two or three times after going to bed, or being told that your snore, talk or kick while sleeping are signs of poor sleep quality," says Dr Samhita Panda, vice-chair, department of sleep medicine, who co-authored the study.
Insomnia stalks worldwide, troubling even celebrities like George Clooney and Lady Gaga. Former US president Bill Clinton, who famously got by on five hours of sleep, underwent a quadruple heart bypass in 2004, a follow-up surgery in 2005 and had two stents implanted in his heart to open his arteries in 2010.
The amount of sleep needed varies with people, with some managing on five hours while others barely functioning without eight to nine hours.
"The recommended duration is between six and eight hours, with most international studies indicating a raised risk of diseases if you sleep for less than five hours and more than 10 hours a day," says Dr Panda.