title: Blunted cardiovascular responses to daytime activities as related to reduced nocturnal blood pressure decline.
abstract: BACKGROUND
  Individuals showing less than a 10% decline in blood pressure at night ("nondippers") are known to be at increased risk for hypertension and other cardiovascular conditions.
  
  
  OBJECTIVE
  This research tested the assertion by Räikkönen et al. (1) that nondippers show blunted cardiovascular responses to activities during daytime hours.
  
  
  METHODS
  Ambulatory blood pressure and impedance monitoring was performed with 149 young adults in Singapore. At each daytime blood pressure reading, participants completed a computerized questionnaire indicating location, posture, physical activities, feelings, and social interactions.
  
  
  RESULTS
  Significant interactions between dipper status and feeling tired, location, posture, and physical activity provided qualified support for the blunting hypothesis. However, blunting of BP responses was not attributable to blunting of either cardiac output or total peripheral resistance responses.
  
  
  CONCLUSIONS
  Nondippers appear to show blunted daytime responses to certain types of daytime activities. However, these effects are limited and appear to be the result of different mechanisms than those responsible for reduced nighttime blood pressure decline.
authors.affiliation: Department of Psychology, National University of Singapore, Singapore 117570. psygb@nus.edu.sg
authors.forename: George D
authors.initials: GD
authors.lastname: Bishop
authors.forename: Jolynn
authors.initials: J
authors.lastname: Pek
authors.forename: Francis
authors.initials: F
authors.lastname: Ngau
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory / Q000295:instrumentation; D002940:Circadian Rhythm; D001330:Electronic Data Processing; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D012890:Sleep; D011795:Surveys and Questionnaires