Obesity . Sleeping too much or too little could make you weigh too much, as well. One recent study showed that people who slept for nine or 10 hours every night were 21% more likely to become obese over a six-year period than were people who slept between seven and eight hours. This association between sleep and obesity remained the same even when food intake and exercise were taken into account.

Headaches . For some people prone to headaches, sleeping longer than usual on a weekend or vacation can cause head pain. Researchers believe this is due to the effect oversleeping has on certain neurotransmitters in the brain, including serotonin. People who sleep too much during the day and disrupt their nighttime sleep may also find themselves suffering from headaches in the morning.

Back pain . There was a time when doctors told people suffering from back pain to head straight to bed. But those days are long gone. You may not even need to curtail your regular exercise program when you are experiencing back pain. Check with your doctor. Doctors now realize the health benefits of maintaining a certain level of activity. And they recommend against sleeping more than usual, when possible.

Depression.. Although insomnia is more commonly linked to depression than oversleeping is, roughly 15% of people with depression sleep too much. This may in turn make their depression worse. That's because regular sleep habits are important to the recovery process.

Heart disease . The Nurses' Health Study involved nearly 72,000 women. A careful analysis of the data from that study showed that women who slept nine to 11 hours per night were 38% more likely to have coronary heart disease than women who slept eight hours. Researchers have not yet identified a reason for the connection between oversleeping and heart disease.

Death. Multiple studies have found that people who sleep nine or more hours a night have significantly higher death rates than people sleeping seven to eight hours a night. No specific reason for this correlation has been determined. But researchers found that depression and low socioeconomic status are also associated with longer sleep. They speculate these factors could be related to the observed increase in mortality for people who sleep too much.