Sleep is not a break from life – sleep is the foundation of life. During sleep, not only the body regenerates, but the brain actively cleanses itself of metabolic waste, memory content is consolidated, hormones are freshly released, and the immune system is strengthened. Prof. Dr. Jörg Spitz explains why chronic sleep deprivation is one of the most dangerous health threats of modern society.
The glymphatic system – a lymphatic network in the brain discovered only in 2013 – works mainly during deep sleep. It pumps cerebrospinal fluid through the tissue, flushing out metabolic waste including the Alzheimer's-associated beta-amyloid. Insufficient deep sleep over years thereby demonstrably favours the development of neurodegenerative diseases.
Melatonin is the conductor of the circadian rhythm – the internal biological clock. It is produced in the pineal gland when the environment is dark, and signals to the body: it is night, time to regenerate. Artificial light – especially blue-light-rich LED and screen light – dramatically suppresses melatonin production and shifts the sleep-wake rhythm.
Prof. Dr. Spitz advocates for "true night" – a sleep environment that corresponds to evolutionary conditions: dark, cool (around 18°C), quiet, and free from electromagnetic interference. He recommends avoiding screens at least one hour before sleep, consistently darkening the bedroom, and maintaining a regular sleep-wake rhythm.
The health consequences of sleep deprivation are dramatic: increased risk of heart disease, weakened immune system, weight gain through altered hunger hormones, poorer cognitive performance, and increased risk of depression. Prof. Dr. Spitz sees sufficient, high-quality sleep as an indispensable pillar of preventive medicine.