Caffeine, a common stimulant for adults, is spreading among teenagers. The coffee habit is a legal one, but the different health needs of adolescents’ developing bodies and full-grown adults mean that there are safety questions. In addition, kids, unlike adults, tend to get caffeine in intense doses, such as from energy drinks or strong coffee.
Even if caffeine isn’t directly harmful, lack of sleep—which caffeine consumption often leads to—can be. Adolescents need more sleep than older people, and caffeine interferes with this. Caffeine may improve alertness and focus in the short term, but sleep serves other important functions that caffeine cannot provide an adequate replacement for.
For example, in one recent study, researchers found that enough sleep can help keep kids from getting diabetes, even if they already have other risk factors. A full night’s sleep—nine hours, approximately—reduces a kid’s likelihood of diabetes and of a prediabetic condition called insulin resistance. That may be why teenagers who have a lot of caffeine-laden drinks habitually tend to grow up to be adults with type 2 diabetes.
Another risk of adolescents substituting caffeine for sleep is heart disease. Caffeine doesn’t place much of a strain on the adult heart, but children and teenagers react differently. Moreover, adolescents who don’t get enough sleep are more prone than their peers to heart disease later in life. Teenagers who reported difficulty falling asleep or having trouble with waking up early have all the hallmarks of heart disease risk, including high cholesterol and a high body-mass index.
However, it’s not all bad news. There is some evidence that caffeine consumption helps children learn. The feeling of awareness you get from a cup of coffee is not illusory, and it works for kids as well. In particular, caffeine stimulates the rhythmic neural activity scientists say is required for learning. It has also been shown to lead to improvements in short-term memory.