Caffeine is the world’s most widely used stimulant. It occurs naturally in coffee, tea, cacao, and some plants, and it is also added to energy drinks, soft drinks, supplements, and certain medicines. In moderate amounts, caffeine can improve alertness, attention, and reaction time. However, its effects depend on dose, timing, individual sensitivity, and how quickly the body clears it. How Caffeine Works Caffeine is thought to be an energy booster, however, that’s not how it works. After it...

Blood sugar is controlled by a continuous exchange among the intestine, liver, pancreas, fat tissue, and skeletal muscle. Of these tissues, skeletal muscle is especially important because it is a major destination for glucose after a meal. Building and regularly using muscle can therefore improve glucose management through two related routes: each bout of contraction increases glucose uptake, and repeated resistance training changes the muscle so that it handles glucose more effectively over...

Sleep is not passive downtime. It is a daily biological process that supports memory, attention, emotional regulation, immunity, metabolism, cardiovascular function, tissue repair, and—in children and teenagers—growth and development. Healthy sleep combines three things: enough total time, good quality with few disruptions, and a schedule that is reasonably consistent. One poor night is usually recoverable; repeated short or fragmented sleep, however, can impair daytime performance...