Many of us need caffeine to get through the day, but too much caffeine can make you toss and turn at night and feel irritable while awake.
The FDA's official recommendation is that adults consume no more than 400 milligrams of caffeine per day, which is the equivalent of about four cups of coffee.
But how can you optimize your caffeine intake to get the most out of it?
The approximate amount for a healthy boost is 100 to 150 milligrams, the equivalent of one or one-and-a-half cups of coffee, says Astrid Nelig, honorary research director at France's National Institute of Health and Medical Research.
Nehrig says you'll start feeling more awake about five minutes after drinking coffee, and the effects peak about 15 minutes to two hours later, depending on whether you've eaten and the speed of your metabolism.
According to the FDA, the official recommendation is for adults to consume no more than 400 milligrams of caffeine per day, which is the equivalent of about four cups of coffee.
However, too much can have negative effects.
A study published last year in the New England Journal of Medicine found that when participants drank as much coffee as they wanted, they slept an average of 30 minutes less on days they didn't drink coffee.
Caffeine's effects on sleep depend on how quickly it is metabolized, said Gregory Marcus, a cardiologist and professor of medicine at the University of California, San Francisco, and lead author of the NEJM study. wall street journal.
It can take up to 10 hours for caffeine to be completely eliminated from your body.
However, experts say that genetic differences mean that some people have slower and faster metabolisms.
The NEJM study found that people with slow metabolisms slept nearly an hour less after drinking coffee, while people with fast metabolisms saw no change in their sleep.
Experts recommend holding off on your first cup of coffee between 9:30 a.m. and 11 a.m. for maximum energy and to avoid irritation.
Research shows that cortisol levels, the main stress hormone, are highest when you wake up, and drinking coffee too early can cause your levels to rise even more, putting you at risk of causing unnecessary agitation.
Research dating back to 2009 Cortisol levels have been shown to be highest in the morning and decline throughout the day, with two major drops at approximately 9:30 a.m. and 1 p.m.
Amanda Mosele, a sports nutritionist in Florida, previously told the health website: Fair enough: “Although there hasn't been much research in humans on the interactions between coffee, cortisol, and circadian rhythms, we know enough about each individually to suggest that before you drink your first cup of coffee in the morning. It might be a good idea to wait a little while.'' That's a good idea.
She added: “Although good for 'waking up,' elevated cortisol levels during times of stress have also been shown to be harmful.”
“So the combination of already elevated cortisol and the additional spike from coffee causes an unnecessary stress response in the body.
“This reaction may be alleviated by waiting an hour or so before enjoying your morning cup of joe.”
If you have a busy afternoon at work, you may want to choose tea, which contains about a quarter of the caffeine found in coffee.
While this may keep you going until the end of your shift, it can also make it difficult to sleep that night. That's because too much caffeine blocks receptors for the hormones adenosine and melatonin, disrupting sleep.
The best time to cut out caffeine is 6 hours before bedtime, and 4pm is best for people who are trying to fall asleep at 10pm.
The Food and Drug Administration (FDA) says these effects should subside within four to six hours.
However, several papers — including one from 2013 — suggests you may need to stop the drug sooner to get a restful night's sleep.
Some experts recommend drinking your last caffeinated beverage at 4 p.m., while others say you should stop at 2 p.m.
Dr. Deirdre Conroy, a sleep expert at the University of Michigan, recommends that people who go to bed at 10 a.m. stop drinking coffee eight hours before bed and by 2 p.m.
She says, “Sensitivity to caffeine varies greatly from person to person, and people who consume caffeine more frequently may have a different reaction than those who do not consume caffeine at all.”
“But in general, our guideline is eight hours before bedtime, and all products containing caffeine should be eliminated.”
Meta-analysis from 2017 It turns out that drinking coffee late at night disrupts your most restful time, slow-wave sleep, and reduces your total sleep time.
Not getting enough sleep is associated with a variety of health problems, including heart disease, kidney disease, high blood pressure, diabetes, and obesity.
The Centers for Disease Control and Prevention recommends that everyone get eight hours of sleep each night, but polls show that one in three adults don't meet this standard.
