Have a nap? Or not?

So in America it’s National Napping Day.

Apparently a NASA study shows that a few winks after lunch can boost a worker’s output by as much as 34 percent.

An afternoon nap ‘is good for your heart’ reported the BBC two years ago.

Various studies have shown that a “power nap” preserves brain power throughout the day:

Hayahsi, M.; Motoyoshi, N.; Hori, T. (2005). Recuperative power of a short daytime nap with or without stage 2 sleep .Sleep, 1;28(7):829-36.

Mednick, S.l Nakayam, K.; Stockgold, R. (2003). Sleep-dependent learning: A nap is as good as a night. Neuroscience, 6(7): 697-698.

Mednick, S. & Stickgold,R. (2002). The restorative effect of naps on perceptual deterioration. Nature Neuroscience. 5 (7): 677-681.

However this week the UK media have recently been reporting that “Taking regular lunchtime siestas could increase the risk of developing Type 2 diabetes, according to research.”

So what to believe?