In Washington Irving’s classic tale, Rip Van Winkle slept for 20 years; when he awoke, he was confused and creaky.

No wonder! Getting too much sleep is associated with Alzheimer’s disease, depression, diabetes and heart disease.

New research shows that, for some, oversleeping is caused by a dysfunction of GABA, a sleep-inducing brain chemical that, when supercharged, acts like anesthesia. But for most, oversleeping is the result of too little or erratic sleep.

Sleep apnea, excessive snoring, lack of daytime physical activity, stress and having a computer, cellphone or TV in your bedroom are common causes of poor sleeping habits that lead to oversleeping. But your body clock wants you to sleep soundly at night so hormones that control metabolism and chemicals that repair cellular damage can do their work. To keep the clock ticking:

• Eat at regular times; sleep in complete darkness; and get as much sunlight (without tanning) as possible.

• Reset your bedtime. Go to bed 15 minutes earlier each night for four nights; stick with the hour-earlier bedtime for another week. Repeat as needed over a couple of months.

• Find solutions for snoring or sleep apnea, from changing position, losing weight, abstaining from alcohol or using a sleep aid called CPAP to correct breathing problems.

Good sleep can make your RealAge up to three years younger, plus it will help you lose weight and cut down on those sugar cravings.