Humans and other mammals show particularly intensive sleeping patterns during puberty. The brain also matures fastest in this period. But when pubescent rats are administered caffeine, the maturing processes in their brains are delayed. This is the result of a study supported by the Swiss National Science Foundation (SNSF).
Children's and young adults' average caffeine consumption has increased by more than 70 per cent over the past 30 years, and an end to this rise is not in sight: the drinks industry is posting its fastest-growing sales in the segment of caffeine-laden energy drinks. Not everybody is pleased about this development. Some people are worried about possible health risks caused in young consumers by the pick-me-up.
Researchers led by Reto Huber of the University Children's Hospital Zurich are now adding new arguments to the debate. In their recently published study conducted on rats, the conclusions call for caution: in pubescent rodents, caffeine intake equating to three to four cups of coffee per day in humans results in reduced deep sleep and a delayed brain development.
Peak level during puberty
Both in humans and in rats, the duration and intensity of deep sleep as well as the number of synapses or connections in the brain increase during childhood, reaching their highest level during puberty and dropping again in adult age. "The brain of children is extremely plastic due to the many connections," says Huber. When the brain then begins to mature during puberty, a large number of these connections are lost. "This optimisation presumably occurs during deep sleep. Key synapses extend, others are reduced; this makes the network more efficient and the brain more powerful," says Huber.