A prospective questionnaire study in 100 healthy sleepers: non-bothersome forms of recognizable sleep disorders are still present.

STUDY
OBJECTIVES: Despite several polysomnographic normative studies and multiple surveys of sleep disorders in the general population, few data have been collected on healthy sleepers. We aimed to survey the characteristics of healthy sleep.
METHODS: We prospectively investigated the sleep history of 100 subjects of a representative population sample who reported undisturbed sleep and in whom relevant sleep disorders were ruled out by a two-step screening procedure. Approximately four subjects had to be contacted for identifying 1 eligible subject who participated.
RESULTS: The median reported time in bed was from 23:00 (21:30-02:00) to 07:00 (05:30-11:00). The total sleep duration was 7.3 h (5-10 h), varying from 7.5 h in the age group ≤ 30 years to 7 h in subjects aged 40-60 years and to 8 h in subjects > 60 years (p = 0.002). The median sleep efficiency was high (93.3%, range: 55.6% to 100%). Fifty-one subjects reported occasional snoring. Forty-five subjects reported sporadic non-bothersome sleep-related movement disorders (25 sleep-related leg cramps, 22 lifetime bruxism, 5 restless legs syndrome), and 36 had a history of sporadic non-bothersome parasomnias (27 nightmares, 12 sleepwalking, 1 sleep paralysis).
CONCLUSION: In this population of healthy sleepers, snoring is the most common finding. Moreover, non-bothersome forms of recognizable sleep-related movement disorders and parasomnias are surprisingly common. These findings may suggest that diagnostic criteria of sleep disorders should not only be based on the presence of symptoms but also account for a minimum frequency or discomfort.