title: Excessive blood pressure elevation upon awakening involves an exaggerated cardiac response to slight physical activity:  a possible mechanism underlying the risk of 'morning surge'.
abstract: OBJECTIVE
  An exaggerated elevation in blood pressure around waking potentially increases the risk of cardiovascular events, even in individuals with normal blood pressure at other-fold of day. The impact of such a transient blood pressure elevation is disproportionate to its short duration, and the reason has not been elucidated. We hypothesize that individuals with such a blood pressure abnormality receive a cardiovascular overload, even from slight physical activities that are frequently undertaken in daily life.
  
  
  METHODS
  A total of 16 patients with essential hypertension (52 ± 15 years) staying at hospital for lifestyle education participated in this study. Morning blood pressure elevation was assessed with 24 h ambulatory blood pressure monitoring. Cardiovascular responses to unloaded pedaling, including blood pressure changes, were assessed in a limited maximum exercise test using an electronically braked bicycle ergometer.
  
  
  RESULTS
  Changes in the systolic blood pressure caused by unloaded pedaling correlated positively with the elevation in systolic blood pressure around waking (r = 0.52, P = 0.05). Moreover, waking elevation of the systolic blood pressure correlated with changes in all of the following cardiovascular variables during unloaded pedaling: heart rate (r = 0.69, P = 0.003), oxygen consumption (r = 0.73, P = 0.001), oxygen pulse (r = 0.62, P = 0.001), and rate pressure product (r = 0.64, P = 0.008), respectively.
  
  
  CONCLUSIONS
  These observations indicate that individuals with prominent blood pressure elevation upon awakening also experience cardiovascular overload from slight physical activities.
authors.affiliation: Department of Cardio-Renal Medicine and Hypertension, Nagoya City University Graduate School of Medical Science, Nagoya, Aichi, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Wakamatsu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takeda
authors.forename: Satoru
authors.initials: S
authors.lastname: Tanaka
authors.forename: Koji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Sumiyo
authors.initials: S
authors.lastname: Yamashita
authors.forename: Tomonori
authors.initials: T
authors.lastname: Sugiura
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Dohi
authors.forename: Genjiro
authors.initials: G
authors.lastname: Kimura
mesh_terms: D000328:Adult; D000368:Aged; D018660:Blood Pressure Monitoring, Ambulatory; D002318:Cardiovascular Diseases / Q000209:etiology; D002940:Circadian Rhythm / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D012306:Risk