New Australian research has shown that sleep duration changes over several days, irrespective of timing, lifestyle, and environment.
“If you incur a sleep debt, your body will signal a need to catch up on extra sleep,” explained study lead author Chin Moi Chow at the University of Sydney in a press release. “As you increase your sleep duration to recover from the debt, your ability to prolong wakefulness increases.”
“Then, as prior wakefulness increases, sleepiness is inevitable, and a need for further sleep develops again.”
The researchers studied 13 healthy young men for two weeks, measuring their sleep patterns with an actigraph, an activity recording device worn on the wrist of the non-dominant arm.
They found that sleep duration followed a sine wave pattern, mostly varying from two to 18 days. This suggests the sleep balance mechanism is always in effect, and any changes in length of sleep are compensated for.
“Our sleep quantity and quality vary according to a range of factors,” Chow said. “Some individuals have a slower accumulation or faster dissipation of sleep pressure, which may define their pattern of total sleep time.”
Variations may also arise from internal factors like differences in body clocks, and external ones like temperature, daylight, and exercise.
“Changing your sleep patterns on weekends, or resetting the pattern through shift work, could alter your sleep duration cycle and could put the body under significant strain,” Chow concluded.
The team hopes to examine the cyclical phenomenon in special groups like insomniacs.
The paper was published in Nature and Science of Sleep.
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