Coffee is one of the most popular stimulants in this country. The caffeine it contains stimulates the nervous system - but can also lead to sleep problems.
Caffeine from drinks such as coffee, cola or energy drinks enters the blood through the intestines after consumption. For most people, it reaches its maximum concentration after just 30 minutes. Some people barely notice a cup of coffee, others still lie awake in bed hours later. In fact, every person reacts differently to caffeine.