Sleep More, Sleep More in Winter – works less says science!
Science provides evidence that feeling gloomy, tired, less productive, and even depressed, could be down to our internal “circadian clocks” programmed by human evolution over centuries.
The circadian clock is an idea used by scientists to measure the human body’s internal sense of time. It’s defined as a “biochemical oscillator” that is synchronized with the sun but also influenced by hormones and the body’s chemicals. Animals still use their circadian clocks to determine when to sleep, wake and eat. The circadian clock tells animals when it’s time to hibernate or reproduce. Humans have evolved recently alongside artificial light, 24/7 availability of food, and set working hours. Despite hints from our bodies, especially during winter, we tend to ignore our circadian clocks.
Greg Murray, professor of psychology at Swinburne University, Australia, as per Wired, says:
“If our body clock is saying it wants us to wake up at 09:00, because it’s a dark winter’s day, but we are getting ourselves up at 07:00 – then we are missing out on a complete sleep phase.”
Chronobiology, the study of how we regulate sleep and wake times, suggests that during winter our sleep requirements change and modern life clashes with this expectation of our bodies during the winter months. Photoreceptors in our eyes are sensitive to blue light and may help to calibrate our circadian clocks and determine sleep regulation.
Murray says, “decreased availability of natural light in the morning in winter should encourage what we call a phase delay.” This means our circadian clocks, perhaps realising that in a less industry and technologically driven world there would be much less to do during darker winter days, is telling us we can sleep for longer.
Studies of pre-industrial societies in South America and Africa found that these communities, as a whole, generally slept for an hour longer in winter. Given their generally warmer and sunnier climates, pre-industrial societies in the colder Northern hemisphere may have slept for even longer in winter.
The hormone melatonin is influenced by, and influences the circadian clock too, scientists found it to be more prevalent in human bodies during winter months.
Social jetlag in winter is an actual thing
Chronobiologist Till Roenneberg explains the resulting difference between what our bodies naturally want to do and what our busy schedules expect of us:
“The discrepancy between what your biological clock wants and what your social clock wants – we have called this social jetlag.”
Social jetlag is apparently well documented and can affect health, wellbeing, and daily functionality. Scientists have discovered that people living at the western edges of time zones, who might have to get up before sunrise when their more easterly peers don’t, have more health problems due to the disruption of their circadian rhythms.
Coping with winter schedules with a conflicting circadian clock may be having similar, perhaps milder, effects and its an idea that’s supported by the theory behind seasonal affective disorder (SAD). Some researchers believe SAD is a more severe response to an out of sync body clock.
The evidence is building that in winter our internal clocks might just be out of sync and with January and February reportedly less productive months anyway, Roenneberg declares:
“Bosses should say ‘I don’t care when you come to work, come when you have slept to your biological end, because we both will win from this situation.”