Running on Empty

The best antidote for an afternoon slump is a cold energy drink, right? Not so fast.

You may be so tired that you could fall asleep right here, right now, on your keyboard. But before you pop open another energy drink, read the list of ingredients on the label. Some so-called "energy" drinks are high in sugar and low in caffeine, a combination that, according to research, could actually have you crashing even harder about 70 to 80 minutes later. A better remedy: a cup of coffee (not decaf) or a 20-minute nap. You'll feel like a new person.

High-sugar drinks make your blood glucose rise -- and fast. Your body's response? Pump out massive amounts of insulin to handle the load. Your system metabolizes all that sugar just as quickly as it entered your system, leading to a big drop in blood glucose about 70 to 80 minutes after you consumed the beverage. Essentially, you crash -- hard. In fact, you'll feel worse than you did before you had the drink, and you'll probably be mentally slower. That's what happened to a small group of sleep-deprived people who performed a computer test to determine their reaction times after drinking a high-sugar, low-caffeine energy drink. Participants performed much worse on the test 70 to 80 minutes after consuming the drink than they did just 10 or 20 minutes after downing it. In other words, they were bum-rushed by the sugar. Power up with a nap, a walk, or a cup of joe instead.

A high sugar content, low caffeine drink does not alleviate sleepiness but may worsen it. Anderson, C., Horne, J. A., Human Psychopharmacology 2006 Jul;21(5):299-303.