Attention coffee addicts. How late in the day is it safe to have a cup of regular coffee? Will that 7 PM cup of Joe keep you from falling asleep? What about coffee at 4 PM?
Journal of Clinical Sleep Medicine concluded, "The magnitude of reduction in total sleep time suggests that caffeine taken 6 hours before bedtime has important disruptive effects on sleep and provides empirical support for sleep hygiene recommendations to refrain from substantial caffeine use for a minimum of 6 hours prior to bedtime."
Summarizing this study, Michael J. Breus, Ph.D, a Clinical Psychologist and both a Diplomate of the American Board of Sleep Medicine and a Fellow of The American Academy of Sleep Medicine wrote, "Even if you don’t feel that late-afternoon cup of coffee has a negative impact on your sleep, this study suggests that it is likely to be interfering nonetheless. This is one reason that I have long recommended a 2 PM cutoff time for caffeine consumption."
The study's author, Christopher Drake, PhD, emphasises the point that late afternoon coffee is harmful to sleep: "'Drinking a big cup of coffee on the way home from work can lead to negative effects on sleep just as if someone were to consume caffeine closer to bedtime. People tend to be less likely to detect the disruptive effects of caffeine on sleep when taken in the afternoon."
Another study in the journal Science Translational Medicine found that caffeine can alter your body's circadian rhythm and disrupt the production of melatonin, a hormone that helps us fall asleep.
An Israeli study showed that late night coffee can reduce the amount of sleep you get by an hour and a half
So there you have it. Six hours before you want to sleep, definitely stop drinking coffee (and other caffeinated beverages.) Make 2 PM your cutoff time, if you want to doubly ensure a good night's sleep.