Recent quotes:

Mid-Day Naps Can Be a Sign of Bad Health | Smart News | Smithsonian

At the end of the study, people who napped for more than an hour were 32 percent more likely to have died than non-nappers, the authors report. As Medical Daily reports, the cause of those deaths varied but included heart disease, cancer and respiratory illness. In other words, the researchers aren't sure what the link between long naps and death risk is, but they think that excessive day time fatigue could likely be indicative of an underlying health problem that their study was not able to tease out.

A nap a day keeps high blood pressure at bay: Catching some midday shut-eye linked to similar drops in blood pressure seen with other lifestyle changes, some medications -- ScienceDaily

"Midday sleep appears to lower blood pressure levels at the same magnitude as other lifestyle changes. For example, salt and alcohol reduction can bring blood pressure levels down by 3 to 5 mm Hg," said Manolis Kallistratos, MD, cardiologist at the Asklepieion General Hospital in Voula, Greece, and one of the study's co-authors, adding that a low-dose antihypertensive medication usually lowers blood pressure levels by 5 to 7 mm Hg, on average. Overall, taking a nap during the day was associated with an average 5 mm Hg drop in blood pressure, which researchers said is on par with what would be expected from other known blood pressure-lowering interventions. In addition, for every 60 minutes of midday sleep, 24-hour average systolic blood pressure decreased by 3 mm Hg. "These findings are important because a drop in blood pressure as small as 2 mm Hg can reduce the risk of cardiovascular events such as heart attack by up to 10 percent," Kallistratos said. "Based on our findings, if someone has the luxury to take a nap during the day, it may also have benefits for high blood pressure. Napping can be easily adopted and typically doesn't cost anything."

Napping and teenage learning

Routine nappers, who napped five to seven days in a week, had sustained attention, better nonverbal reasoning ability and spatial memory. How long to nap is also an important question? The sweet spot is between 30 to 60 minutes. A nap longer than one hour interferes with circadian rhythm. Participants who slept between 30 to 60 minutes produced better accuracy in attention tasks as well as faster speed. She recommends not to nap after 4 p.m., nor over-nap. Researchers were surprised to find a positive relationship between midday napping and nighttime sleep, which is different than the literature. Habitual nappers (who napped more often) tended to have a better nighttime sleep. “That’s different than the findings in the United States, where napping may serve as a function to replace sleep lost from the previous night. Consequently, that may interfere with the following night’s sleep,” Ji said. “In China, a midday nap is considered a healthy lifestyle. Routine nappers are more likely to experience healthy nighttime sleep. So routine nappers are essentially trained to sleep well and sleep more at night.”

Magical napping

I just want to add that we've done some studies looking at naps in terms of the memory processing and have been rather stunned, really, by the fact that in almost every experiment that we've tried, an hour-and-a-half nap seems to do as much good for memory processing as an entire night of sleep, and we continue to ponder that and sort of conclude that OK, we just don't get it yet. But in studies where six hours of sleep at night seems not enough to lead to consolidation of memory of a particular task, an-hour-and-a-half nap will. So there's something, at least from the memory perspective, rather magical and unusually efficient about napping as opposed to nocturnal sleep.