Siestas could be the secret to a more active older brain
An hour’s siesta can prevent your brain ageing by five years when it comes to memory and thinking, scientists say.
According to the study, a 60-minute sleep was the optimum amount of time, with a shorter or longer period not producing the same result.
Scientists analysed 3000 Chinese people over the age of 65, 60 per cent of whom said they had a nap after lunch, ranging between 30 and 90 minutes, with an average of 63 minutes.
They were asked a series of simple questions about dates and seasons. After submitting their responses, the pensioners were given a basic maths problem and asked to memorise words and copy simple geometric figures.
The study, which was carried out by the Health in Ageing Foundation and published in Journal of the American Geriatrics Society, concluded that the people who took an hour-long nap after lunch performed better in mental tests than the people who did not nap.
Those who slept for about an hour also did better than people who took shorter or longer rests.
People who took no naps, short naps or longer naps experienced decreases in their mental ability that were between four and six times greater than the people who took hour-long naps.
Junxin Li, lead author of the study, said: ‘‘These people also experienced about the same decline in their mental abilities that a five-year increase in age would be expected to cause.
‘‘Cognitive function was significantly associated with napping. Between-group comparisons showed that moderate nappers had better overall cognition than non-nappers or extended nappers.
‘‘Non-nappers also had significantly poorer cognition than short nappers. Moderate napping was significantly associated with better cognition than non- and extended napping, after controlling for demographic characteristics, body mass index, depression, instrumental activities of daily living, social activities, and nighttime sleep duration.’’
David Reynolds, chief scientific officer at Alzheimer’s Research UK, said: ‘‘This study adds to growing evidence that sleep has a beneficial impact on learning and memory, and it’s positive to see that this holds true in a study of older adults.
‘‘Sleep disturbances are common in Alzheimer’s, and while there are studies investigating the role of sleep in the disease, this study has not looked at whether afternoon naps may protect against Alzheimer’s or other dementias.’’
Last year scientists found that a long afternoon nap could help to boost the brain power of men, and that women benefited from a longer night’s sleep.
Researchers from the Max Planck Institute in Munich believe that the differences between how sleep affects the sexes could be because of the way that men’s and women’s brains are structured as well as how hormonal changes affect the body during the day.