Researchers found that those who sleep more or less than seven hours a day are at a raised risk of developing coronary heart disease.
The study found that the subjects who said they slept nine hours or longer a day were one-and-a-half times more likely than seven-hour sleepers to develop heart disease, according to Times of India.
Study leader Dr David Dinges, who heads the Division of Sleep and Chronobiology at the University of Pennsylvania School of Medicine in Philadelphia, said: "The additional hour or two of sleep in the morning after a period of chronic partial sleep loss has genuine benefits for continued recovery of behavioural alertness.
The bottom line is that adequate recovery-sleep duration is important for coping with the effects of chronic sleep restriction on the brain."
Inadequate sleep is known to impair the ability to think, handle stress, maintain a healthy immune system, and keep emotions in check.
When people lose sleep, their concentration drops and they suffer memory lapses. The brain falls into "rigid" thought patterns, making decision making and problem solving difficult.
The effects can have a big impact on work performance, yet stress and long working hours frequently mean people in busy jobs get too little sleep during the week.
Experts say most people need between 7.5 and nine hours of sleep a night, although some get by on less and others require more, The Press Association reports.