Whether you're an early bird or a night owl, your work and sleep schedule can affect your health — and choosing the best schedule to keep you in the best condition can depend on your age.
So says a CNN report that cites research on the biological clock that regulates physical, mental and behavioral changes within the human body over a 24-hour cycle — known as circadian rhythms — and how those rhythms change as people age.
Teens and young adults, for instance, respond to the hormone melatonin, which governs when they feel sleepy (later) and when they wake (also later).
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Fighting that late-late schedule can cause problems, since during that period of life, the body releases melatonin later in the day. For adolescents, it comes around 10 p.m., hence the determination to stay up to finish the late movie. But they will also find it more difficult to wake up early, since their bodies got such a late start on sleep.
Adults in their 30s and 40s, on the other hand, can hew more closely to that night-owl or early-bird designation, something that's apparently governed by one's genes — but with a caveat. Irregular and overnight shifts can negatively impact not just the body's health, but also the brain's.
The report cites a Swedish study indicating that shift workers experienced cognitive impairment — and so did workers who had quit shift work less than five years previously, suggesting that the negative effects of shift work took at least five years to recover cognitive performance.
But once you hit 40, it's all downhill — as far as pulling all-nighters, that is. A study published earlier this year suggested that a reduced schedule — of about 25 hours a week, or a three-day workweek — is the optimum arrangement for adults 40 and older. (Good luck getting that arrangement from your boss.)
But the study finds working up to 25 hours a week stimulated brain activity, but past that point it actually reduced cognitive performance. Excessive hours, of course, were shown to produce physical and/or mental stress.
So what does all this mean? It can mean you're letting yourself in for health problems that go beyond cognitive impairment, since two other studies — the first in the Journal of Occupational and Environmental Medicine, and the second in the Lancet — found, respectively, that women in their 20s, 30s and 40s working 60 or more hours a week could triple their risk of diabetes, cancer, heart trouble and arthritis, and that working 55 hours or more per week could increase the risk of heart disease and stroke in adults.
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