How can I stay more alert late in the day?

Automobile accidents are more common at night because most people start to lose their ability to concentrate maximally after they have been awake for more than eight hours. A study from France showed that much of your early morning alertness can be restored just by napping or drinking coffee prior to driving (Annals of Internal Medicine, June 2006).

Researchers tested young drivers during the day and again in the evening after drinking coffee containing 200 mg of caffeine, taking a 30-minute nap in the afternoon, or a placebo of decaffeinated coffee. They drove 125 miles between 6:00 and 7:30 PM, and again between 2:00 and 3:30 AM. The doctors compared self-rated fatigue and sleepiness, inappropriate line crossings from video recordings, and polysomnographic recordings during the nap and subsequent sleep. Night-time driving performance was similar to daytime performance for 75 percent of the participants after coffee, for 66 percent after napping, and for only 13 percent after the placebo. This study agrees with many other studies that show that both napping and stimulants improve performance in activities that require concentration or memory in the afternoon or evening.

Checked 10/1/18

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