So how does it work? “When coffee is consumed, the caffeine gets absorbed and starts affecting the nervous system within 30 minutes,” says Dr. Bortecen. Therefore, a brief nap right after a cup of coffee will give enough time for the body to absorb and process the caffeine and enhance alertness, immediately after the power nap.
Because the coffee remains in your blood stream for several hours, when people take a short nap of 15-20 minutes or less, that caffeine kick will really hit right after they wake up and it’ll linger for a few hours. “Caffeine is mainly metabolized in the liver and has a half-life of 4 to 5 hours,” he explains.
Plus, caffeine increases energy metabolism throughout the brain, improving learning, memory, performance, and coordination abilities. So you might feel more alert and productive, eager to tackle any work demands or long car rides, he explains. (There’s also some evidence to suggest that you might want to drink some before a workout, too.)
It’s important to make sure that you’re timing the coffee nap properly to fully reap the benefits. “Many people experience tiredness and sleepiness a few hours after lunch during the mid-afternoon, so a brief coffee nap can improve alertness and help enhance and improve short-term memory and mood,” he says. (Here are some tips for taking a nap at the office.)
What’s more, the duration of the nap is also important. You should limit your nap to between 15 and 20 minutes. “Naps longer than an hour generally include a slow-wave sleep pattern and people usually experience grogginess when they wake up,” he explains.
“An afternoon coffee nap will give enough boost for the rest of the day until the caffeine is metabolized, but you should be cautious not to delay the nap after drinking your coffee,” says Bortecen. So shut those eyes right away to avoid missing that 30-minute window for the caffeine to kick in. “Otherwise, it will alter your sleeping pattern and negatively affect your performance,” he warns. Don’t try a coffee nap too close to bedtime, either: drinking caffeine and napping too late in the evening can mess with your sleep patterns and make it harder to fall asleep, he says.
Don’t like coffee? Good news — you can actually still benefit by getting caffeine from a different source, he says.
“If you do not like coffee, there are other alternatives. Several other drinks, food products and over-the-counter medicines also contain caffeine,” he says. Try coffee-flavored foods, like ice cream or yogurt, chocolate, energy drinks, tea, protein bars, or enhanced waters.
So if you already love caffeine and napping, it’s worth giving the coffee nap a shot. Just be mindful of your daily consumption to avoid unwanted side effects from excess caffeine. “People who consume too much caffeine regularly might experience caffeine withdrawal and suffer from drowsiness, lack of energy and headache,” he says. Keep track of your daily caffeine consumption: according to the FDA, you should limit yourself to around 400mg a day.