Nighttime blood pressure in normotensive subjects with chronic insomnia: implications for cardiovascular risk.
OBJECTIVE
To assess as whether insomniacs have higher nighttime blood pressure (BP) and a blunted day-to-night BP reduction, recognized markers of increased risk of cardiovascular morbidity and mortality.


METHODS
Prospective case-control study.


METHODS
University hospital-based sleep research laboratory.


METHODS
Thirteen normotensive subjects with chronic primary insomnia (9 women, 42 +/- 7 y) and 13 sex- and age-matched good sleepers.


RESULTS
Subjects underwent 2-week sleep diary and 3 sleep studies to provide subjective and objective sleep variables, and 24-h beat-to-beat BP recording to provide daytime, night-time and day-to-night BP changes ([nighttime-daytime]/daytime)*100) (BP dipping). Spectral analysis of the electroencephalogram (EEG) was also performed during sleep of night 3 to assess EEG activity in the beta frequency (16-32 Hz), a measure of brain cortical activation. Nighttime SBP was higher (111 +/- 15 vs 102 +/- 12 mm Hg, P < 0.01) and day-to-night SBP dipping was lower (-8% +/- 6% vs -15% +/- 5%, P < 0.01) in insomniacs than good sleepers. Insomniacs also had higher activity in EEG beta frequency (P < 0.05). Higher nighttime SBP and smaller SBP dipping were independently associated with increased EEG beta activity (P < 0.05).


CONCLUSIONS
Higher nighttime SBP and blunted day-to-night SBP dipping are present in normotensive subjects with chronic insomnia and are associated with a hyperactivity of the central nervous system during sleep. An altered BP profile in insomniacs could be one mechanism implicated in the link between insomnia and cardiovascular morbidity and mortality documented in epidemiological studies.
Lanfranchi
Paola A
PA
Department of Medicine, Division of Cardiology, Hôpital du Sacré-Coeur de Montréal and Université de Montréal, Québec, Canada. Paola.Lanfranchi@umontreal.ca
Pennestri
Marie-Hélène
MH
Fradette
Lorraine
L
Dumont
Marie
M
Morin
Charles M
CM
Montplaisir
Jacques
J
D000328:Adult; D001611:Beta Rhythm; D001794:Blood Pressure / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011446:Prospective Studies; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D015996:Survival Rate