Why you shouldn’t nap for more than 40 minutes - it could harm your health

Diabetes expert says short naps may be good for us but longer siestas are definitely bad for us, being associated with increased risk of suffering high blood pressure and other conditions

PUBLISHED : Wednesday, 23 March, 2016, 9:00pm
UPDATED : Wednesday, 23 March, 2016, 9:00pm

Taking long naps or being excessively tired during the day is associated with a higher risk for developing metabolic syndrome, according to a new study by University of Tokyo researchers. Specifically, napping for 40 minutes or longer was associated with a steep increase in the risk of developing metabolic syndrome – a collection of health conditions such as high blood pressure, high cholesterol, excess fat around the waist and high blood sugar that all increase a person’s risk for heart disease.

Poor diet blamed for rise in metabolic condition

The research team, led by diabetologist Dr Tomohide Yamada, evaluated data from 21 observational studies involving 307,237 Asian and Western subjects. Participants reported their daytime sleepiness and napping habits through a questionnaire, and their responses were compared to their history of metabolic syndrome, type-2 diabetes and obesity. The results showed a J-shaped relationship between time spent napping and metabolic syndrome risk.

Subjects who napped for less than 40 minutes did not show any increased risk for metabolic syndrome, but beyond 40 minutes, risk sharply rose. Napping for 90 minutes appeared to increase metabolic syndrome risk by as much as 50 per cent, as did being excessively tired during the day. Interestingly, there was a slight dip or decrease in the risk of metabolic syndrome among those napping less than 30 minutes.

“Sleep is an important component of our healthy lifestyle, as well as diet and exercise,” Yamada says. “Short naps might have a beneficial effect on our health, but we don’t yet know the strength of that effect or the mechanism by which it works.”

BPA substitute can trigger fat cell formation

The harmful effects of bisphenol A (BPA) are now well-known enough that most people are aware of choosing BPA-free plastic food containers. But it seems its substitute chemical, bisphenol S (BPS), has its own effects on the body’s hormones.

A study published in the journal Endocrinology shows that exposure to BPS can encourage the formation of fat cells. “Our research indicates BPS and BPA have comparable effects on fat cells and their metabolism,” says senior author Ella Atlas of Health Canada, the federal department responsible for helping Canadians maintain and improve their health. “The study is the first to show BPS exposure can induce the formation of human fat cells.”

The researchers created a human cell model to test the effects of BPS exposure. They used human cells called preadipocytes taken from the hip, thigh or abdomen of female volunteers. Groups of cells were exposed to various concentrations of BPS during a 14-day period. Researchers found that the cells exposed to the smallest amounts of BPS as well as the cells exposed to the highest concentrations exhibited the largest accumulation of lipids, while moderate amounts had a smaller effect.

Use mindfulness-based stress reduction to relieve chronic lower back pain

Among adults with chronic lower back pain, both mindfulness-based stress reduction and cognitive behavioural therapy resulted in greater improvement in back pain and functional limitations when compared with usual care, according to a study in JAMA. Mindfulness-based stress reduction (MBSR), through meditation and yoga, focuses on increasing awareness and acceptance of moment-to-moment experiences including physical discomfort and difficult emotions.

Scientists at the Group Health Research Institute in Seattle, in the United States, randomly divided 342 adults aged 20 to 70 years with chronic lower back pain (for an average 7.3 years) into three groups: one received MBSR, another cognitive behavioural therapy and the last group, usual care. CBT (training to change pain-related thoughts and behaviours) and MBSR were delivered in eight weekly two-hour groups. Usual care included whatever other treatment, if any, the participants received.

The researchers found that at 26 weeks, the percentage of participants with clinically meaningful improvement on a measure of functional limitations was higher for those who received MBSR (61 per cent) and CBT (58 per cent) than for usual care (44 per cent). The percentage of participants with clinically meaningful improvement in pain at 26 weeks was 44 per cent in the MBSR group and 45 per cent in the CBT group, vs 27 per cent in the usual care group. Findings for MBSR persisted with little change at 52 weeks for both primary outcomes.

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