title: Temporal changes in cardiorespiratory fitness and the incidence of hypertension in initially normotensive subjects.
abstract: OBJECTIVE
  Low-cardiorespiratory fitness (CRF) has been associated with incident hypertension, but whether temporal changes in CRF are associated with incident hypertension in initially normotensive subjects are not known. We investigated the relationship of baseline CRF and longitudinal changes in CRF with incident hypertension in initially normotensive subjects.
  
  
  METHODS
  Subjects were 3,831 men who participated in two health examinations during 1998-2009. All subjects were free of cardiovascular diseases and hypertension at baseline. CRF was directly measured by peak oxygen uptake using expired gas analysis during a standard treadmill test.
  
  
  RESULTS
  During an average of 5 years of follow-up, 373 (9.7%) subjects developed hypertension. The incidence of hypertension was inversely associated with baseline CRF quartiles [Q1 (lowest) 11.8%, Q2 10.4%, Q3 9.1%, and Q4 (highest) 7.5%; P < 0.05 for trend]. The relative risk (RR) of incident hypertension in the lowest CRF quartile versus the highest CRF quartile was 1.69 (95% CI: 1.22-2.34) after adjustment for risk factors. Each metabolic equivalent increment higher peak oxygen uptake at baseline examination was associated with 10% (RR 0.90, 95% CI: 0.83-0.98) lower incidence of hypertension in multivariate adjusted model. Subjects whose CRF decreased (<-1.18 ml/kg/min per year) over time had a 72% increased risk in developing hypertension (RR 1.72, 95% CI: 1.20-2.49) compared to subjects with increased CRF (>0.13 ml/kg/min per year) after adjustment for risk factors.
  
  
  CONCLUSIONS
  These results demonstrate that both baseline CRF levels and changes in CRF over time were associated with the incidence of hypertension independent of risk factors.
authors.affiliation: Department of Sports Informatics, University of Seoul, Seoul 130-743, South Korea.
authors.forename: Sae Young
authors.initials: SY
authors.lastname: Jae
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Heffernan
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Yoon
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Mercedes R
authors.initials: MR
authors.lastname: Carnethon
authors.forename: Bo
authors.initials: B
authors.lastname: Fernhall
authors.forename: Yoon-Ho
authors.initials: YH
authors.lastname: Choi
authors.forename: Won Hah
authors.initials: WH
authors.lastname: Park
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis; D001794:Blood Pressure; D005080:Exercise Test; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D015994:Incidence; D007958:Leukocyte Count; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010366:Peak Expiratory Flow Rate; D010809:Physical Fitness; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors