Long-term sleep impairment is related to an increased risk of somatic health problems, e.g. overweight, Type 2 diabetes, cardiovascular disease and premature death. Avoidance of caffeine, alcohol, energy-rich or fatty foods and light from computer screens close to bedtime may counteract impaired sleep. A quiet, dark and well-tempered bedroom and physical activity during the day may have a positive impact on sleep. Impaired sleep may be related to stress and conditions at home or at work. Psychological sleep treatment is free of adverse side effects with effects comparable to effects of medical treatment.