A new study has revealed that consuming caffeine even six hours before bed time is likely to have disruptive effects on sleep. The findings of the study have been published in the Journal of Clinical Sleep Medicine.
Researchers led by Christopher Drake, PhD, investigator at Michigan's Henry Ford Hospital's Sleep Disorders & Research Center analyzed the sleep-disruptive effects of caffeine consumption at various time periods before bedtime.
The study involved 12 participants including men and women, who were healthy and normal sleepers. The participants were asked to follow normal sleep schedules and maintain sleep diaries, use at-home sleep monitors so as to allow the researchers to track their sleep.
The participants were given pills that contained doses of caffeine. They were asked to consume three pills a day for four days. While one of the pills contained 400 mg of caffeine, the other two were placebo pills. On one of the four days, all three pills were a placebo, reported ANI.
Participants had to consume the pills at three different timings - one at bedtime, one at three hours before bedtime and one at six hours before bedtime. This allowed the researchers to measure the sleep disruptive effects of caffeine on the sleepers. They found that the participants witnessed significant disruptions in sleep at all three different points.
The study found that pills consumed at bedtime, three hours before bedtime and six hours before bedtime reduced total sleep time of the participants. Consuming coffee even six hours before bedtime reduced the sleep time by more than one hour, according to the researchers.
People who consume coffee during afternoon are less likely to detect disruptive effects in their sleep. The study concludes that people should avoid drinking caffeine after 5 p.m. in the evening so as to have a healthy sleep in the night.
Best time to drink coffee
Another study revealed last month that the best time to consume caffeine is between 9:30 a.m. and 11:30 a.m. as that is the time when the cortisol levels drop. Cortisol is a stress hormone and their production is strongly related to alertness, Steven Miller of the Uniformed Services University in Bethesda, Md., wrote in science news blog NeuroscienceDC.
According to Miller, the cortisol levels peak between 8 and 9 a.m, between noon and 1 p.m. and between 5.30 and 6.30 p.m. If one consumes caffeine when cortisol levels are at its peak, then he/she can develop a tolerance to caffeine. This means that the drug will be less effective in the body.
Miller revealed that the best time to drink coffee is between 9:30 a.m. and 11:30 a.m., when the cortisol levels drop before its next spike.
To report problems or to leave feedback about this article, e-mail:
To contact the editor, e-mail: