A new Japanese study shows that scrimping on sleep is especially bad for you when the weather is hot. By Li Yuling
Photo: tomwang / www.123rf.com
Singapore’s highest temperature today was recorded at 32 deg C, and the weather forecast predicts the same heat tomorrow. Yikes.
If you plan on being outdoors a lot these days, you might want to go to bed earlier. A new study conducted in Japan and published in the journal Occupational & Environmental Medicine has found that insufficient sleep raises the risk for physical and mental strain – while working in the heat.
Researchers studied two groups of men: One group had about seven to eight hours of sleep. The sleep-restricted group clocked only four hours of shuteye. Both groups spent 40 minutes on moderate walking in a hot room of about 35 deg C in the morning as well as in the afternoon.
The team then assessed the level of physical strain by measuring the men’s temperature and heart rate. The men rated their own levels of sleepiness, mental and physical fatigue as well as feelings of heat, cold, mood and thirst. Researchers also measured the men’s reaction times.
The sleep-restricted group fared significantly poorer in all aspects, compared to those who got enough sleep.
Interestingly, the study also found that an afternoon nap made things better for the sleep-restricted. Their self-reports of fatigue and sleepiness became better, and their reaction times also improved. Their physical scores did not change, however.
The take-home message: Don’t miss out on precious sleep – especially now that we’re experiencing the hotter months in Singapore. And if you really have to burn the midnight oil, find time to take a nap the following day.