Tue, 03 Nov 2009 16:23:2
Ayinde O. Chase - AHN Editor
Montreal, Quebec (AHN) - According to a new study people who work the night-shift should avoid drinking coffee if they wish to improve their sleep. Researchers found that the main byproduct of coffee, caffeine, interferes with sleep and this side-effect worsens as people age.
"Caffeine is the most widely used stimulant to counteract sleepiness, yet it has detrimental effects on the sleep of night-shift workers who must slumber during the day, just as their biological clock sends a strong wake-up signal," says study leader Julie Carrier from the University of Montreal. "The older you get, the more affected your sleep will be by coffee."
Twenty-four men and women participated in the study: one group was aged 20 to 30, while a second group was aged 45 to 60. Everyone spent two sleepless nights in lab rooms before being allowed to sleep. "We all know someone who claims to sleep like a baby after drinking an espresso. Although they may not notice it, their sleep will not be as deep and will likely be more perturbed," says Professor Carrier.
Both participant groups had to take a pill three hours before sleeping; either 200 milligrams of caffeine or a lactose-based placebo. All of the study participants who consumed caffeine pills had their sleep affected. A group that had a markedly noticeable change was that of the older participants who slept 50 percent less than usual. In both age groups, caffeine decreased sleep efficiency, sleep duration, slow-wave sleep (SWS) and REM sleep.
The combined influence of age and caffeine made the sleep of middle-aged subjects particularly vulnerable to the circadian waking signal. Study researchers suggest that the lower brain synchronization - caused by age and caffeine - produces greater difficulty in overriding circadian waking signals during daytime which leads to fragmented sleep.
These study results have implications for the high proportion of the population who uses caffeine to cope with working nights, especially the middle-aged. Researchers suggest everyone over 40 reduce their coffee consumption, especially if they work at night and compounds on recent findings that suggest reducing coffee consumption is the best way to improve sleep for the middle-aged.
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