Sleep disorders and the failure to lower nocturnal blood pressure.
OBJECTIVE
The failure to lower systolic blood pressure at night (called non-dipping) and sleep apnea are both associated with adverse cardiovascular outcomes. Sleep apnea is a common cause of non-dipping blood pressure.


RESULTS
Sleep apnea increases night time blood pressure through enhanced cardiac pre-load, sleep disturbance and hypoxia. Hypoxia elicits increased levels of norepinephrine, endothelin and erythropoetin. Patients with sleep apnea tend to be elderly and obese, so they have poor endothelial nitric oxide release and blunted baroreflexes. They thus have several stimuli for high blood pressure and poor compensatory mechanisms to lower blood pressure.


CONCLUSIONS
Non-dipping patients without sleep apnea have evidence of volume overload and correct their blood pressure pattern in response to diuretics. Individuals with sleep apnea have evidence of increased cardiac pre-load from episodes of negative intrathoracic pressure. Their daytime blood pressure responds poorly to many drugs, but beta blockers may be effective. Their night time blood pressure responds only slightly to therapy of their sleep apnea with continuous positive airway pressure, even though continuous positive airway pressure decreases their norepinephrine, erythropoetin and endothelin levels.
Ziegler
Michael G
MG
University of California San Diego, 92103-8341, USA. mziegler@ucsd.edu
D001794:Blood Pressure / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology; D002318:Cardiovascular Diseases / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology*; D016232:Endothelins / Q000502:physiology; D004921:Erythropoietin / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D007674:Kidney Diseases / Q000503:physiopathology; D009569:Nitric Oxide / Q000502:physiology; D044469:Racial Groups; D012121:Respiration, Artificial; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000503:physiopathology; D012893:Sleep Wake Disorders / Q000503:physiopathology*
D016232:Endothelins; D004921:Erythropoietin; D009569:Nitric Oxide