New research on the relationship between caffeine and sleep.

New research on the relationship between caffeine and sleep. Watch: Is Too Much Coffee Bad for You?

As if getting a good night's sleep now versus when you were in your twenties isn't hard enough, a recent study in Sleep Medicine suggests drinking coffee may be making it worse. Researchers at the University of Montreal examined how caffeine affected sleep quality in 24 men and women ranging in age from 20 to 60 years. Participants were deprived of sleep for 25 hours and then given 200 milligrams of caffeine (roughly the amount in 16 ounces of brewed coffee or four to five 8-ounce cups of tea) before they were allowed to get some shuteye.

As one would expect, all the participants slept less, and less restfully, than when they completed the same experiment minus the caffeine. They also experienced less slow wave sleep, the deep sleep that helps you feel refreshed. Interestingly, caffeine appeared to interfere more with the middle-aged subjects' sleep.

"There's a major decrease in slow wave sleep as early as age 40," says Julie Carrier, Ph.D., lead researcher and a professor of psychology at the University of Montreal. "I encourage people, especially as they get older, to try to reduce their caffeine consumption as much as possible." Rather not give up your java or tea? Minimize caffeine's sleep-stealing effects by drinking it as early in the day as you can.

May/June 2010