While launching into an off-key rendition of the Pointer Sisters’ classic “I’m So Excited” isn’t the reaction most of us have after drinking too much coffee, maxing out on caffeine can cause plenty of negative side effects—trouble sleeping, anxiety, upset stomach and the frequent need to pee chief among them.
Like any other stimulant to your central nervous system, the key to having fun with this drug is taking the right amount at the right time. (In other words, not so much that you need Zack Morris to calm you down.)
Healthy people looking for a boost can safely consume up to 400 milligrams of caffeine a day, which translates to about…
- 4 cups of coffee;
- 10 cans of Coke;
- or 2 shots of 5-Hour ENERGY
And although 100 milligrams of caffeine will give you the same jolt if it comes from Dr. Pepper or Dunkin’ Donuts, all caffeine isn’t created equally. The caffeine in coffee and tea is naturally occurring (it functions as an insecticide that protects the plants), while the caffeine found in soda is mostly manufactured in China and added to the beverage blend along with sugar, artificial coloring and carbonation.
Frank Ritter, who studies caffeine at Penn State’s College of Information Sciences and Technology, says you’re considered “in the zone” if you’ve consumed between 200 milligrams and 400 milligrams of caffeine. To get there, he recommends seeking out the first blast of caffeine “fairly quickly,” with subsequent ones spaced out and eventually tapering hours before you go to bed. Exactly how many hours you need to let the effects of caffeine subside depends on your body. In general, caffeine has a half-life of 5-6 hours in healthy adults, meaning that half of the caffeine in your 8 a.m. cup of coffee is still bouncing around your brain at 1 p.m.
If you find yourself in an extremely sleep-deprived state—due a grueling travel schedule, wailing newborn or a House of Cards marathon—you should consume caffeine frequently, but at a very low dose. A 2004 Harvard Medical School study demonstrated that consuming small amounts of caffeine (i.e., a half a can of Coke for a 175-pound man) every hour helped participants feel less groggy and perform better on cognitive tests after staying awake for more than 24 hours straight.
If you think a low-dose regimen isn’t powerful enough, you can certainly kick your consumption up a notch. As long as you avoid pure, powdered caffeine, you’re unlikely to experience any serious harm.
Though judging by Jessie Spano’s epic “I’m So Excited” meltdown, you might want to steer clear of caffeine pills, too.
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