How Does Your Body Clock Work? Contrasting Light And Heat Levels Can Disrupt It
After Daylight Saving time rolled the clock back this weekend, your body rhythms are probably a bit off. A new study from the University College London has shed light on the workings of this internal system by showing that the body clock function of fruit flies can break down when light and temperature levels are out of sync throughout the day.
Researchers examined the activity levels of flies after exposing them to light and heat at times different from their “natural” cycle. After adjusting these environmental factors to a lag of about six hours, the team examined a breakdown of typical clock function — resulting in disruptions to behavior and clock-controlled molecular signals.
"The body clock is a naturally evolved entity so it functions best within naturally-occurring conditions," explained lead author Ross Harper, according to a press release. "Changes in sunlight cause changes in temperature, and both are used to sense time. The time lag between light and temperature naturally varies, so the clock can compute an average time for smaller changes.”
“For very large differences, such as a heat spike at midnight, the system ignores temperature as it is no longer a reliable indicator of 'daytime.' In between these lies a zone of confusion, where the clock can't combine the cues anymore but can't yet ignore them either. As mammals, including humans, are subject to similar evolutionary constraints, it is likely that similar systems apply to our clocks," Harper continued.
Further research will be able to better define this effect on humans’ body clocks because we regulate temperature internally, but the body temperature of insects completely depends on their external environment.
Source: Harper R, Albert JT, Stanewsky R, et al. Body clock function can break down when light and temperature levels throughout the day are out of sync. Cell Reports. 2016.
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