n afternoon nap is one of the joys of life, although excessive nap may signal that all is not well. A new study published in Alzheimer's & Dementia suggests that daytime naps may be an early sign of Alzheimer's disease. Researchers compared the brains of 13 after the death of 13 with Alzheimer's with the brains of seven control subjects and found that those with brain disease had protein accumulation, tau, in areas of the brain involved in alertness.
"Some people have been napping all their lives, no problem," said Lea Greenberg, professor of neuropathology at the University of California, San Francisco. "In some cultures, people will have a daily siesta ̵
It is not entirely clear whether the rush is good for you or not. Some studies suggest that they reduce stress and increase cognitive function, but one study suggests that pulling is associated with an increased risk of mortality and there is certainly good reason to believe that daytime sleepiness – as in the Alzheimer's study – may be daytime marker
For many people, daytime naps are mostly a sign that you don't sleep enough at night, says Dr. Neal Stanley, a sleep expert and author of How to Sleep Well. "If you feel sleepy during the day, you should consider sleeping. This is what the body needs – it does not need to be alert for caffeine; it needs sleep. "The feeling of noticing is 'drowsiness,'" he says, not "fatigue," which could be more psychological and stress-related.
So how do you sleep well? The key, Stanley says, is duration. Choose a nap of 20 or 90 minutes. "When you fall asleep, you will quickly go through the milder stages of sleep in your first deep sleep. You don't want to wake up in a deep sleep, because that's when you wake up and feel worse than before. "Annoyance for 20 minutes means you will wake up before you go into deep sleep; a 90 minute nap means you will complete the sleep cycle.
Once you understand the time it takes to fall asleep – some people are better off taking a nap than others, but, says Stanley, "a healthy adult will sleep between five and 12 minutes" – you can set an alarm allowing a period of 30 up to 40 minutes for a short nap and up to two hours for a longer nap.
A good time for a nap is during the body's natural immersion in the afternoon, between 2:00 pm and 4:00 pm (the circadian rhythms of older people change, Stanley says, so they can begin to feel more drowsy earlier in the day). "You don't really want to sleep long before then, because then you'll eat in your night's sleep," he says. The point, he stresses, is to get yourself a good night's sleep, which will ensure that you probably don't need to sleep.