Evening coffee has sparked controversy for years. Some people fall asleep without difficulty, while others toss and turn for half the night. However, a growing body of research suggests the question of whether coffee makes it harder to fall asleep may be too simplistic. What appears to matter far more is what happens in the brain during sleep.
Scientists studying the effects of caffeine on sleep are increasingly turning to EEG, or electroencephalography, a method used to record the brain's electrical activity. Thanks to EEG, it is possible to observe not only sleep duration or moments of awakening, but also the biological quality of sleep itself.
"EEG allows scientists to see not only whether a person is sleeping, but also how the brain is sleeping. Classical sleep assessment measures sleep duration and its stages, whereas quantitative EEG analysis reveals more subtle changes, such as reduced slow-wave activity, which is an important marker of sleep depth and its restorative character," said Prof. Donata Kurpas of the Department of Nursing at Wroclaw Medical University.
Slow waves are one of the key components of deep sleep, the phase responsible for bodily regeneration, restoration of energy resources, and proper brain function.
