Cardiovascular stress and sleep.

This review summarizes briefly the present knowledge on sleep-related factors in ischaemic heart disease. A marked circadian rhythm in the frequency of onset of acute myocardial infarction has been found, but the exact mechanism is not known. The circadian variation is possibly explained by several mechanisms. The best documented is sleep apnoea syndrome, which seems to be a risk factor for ischaemic heart disease and stroke. Stressful REM-sleep seems to be potentially arrhythmogenic in patients with decreased cardiopulmonary function. The role of coronary spasm, increased thrombocyte aggregation and mental stress in sleep disorders is still poorly understood.