title: Association between the physical activity and heart rate corrected-QT interval in older adults.
abstract: OBJECTIVE
  Increased physical activity can reduce the incidence of cardiovascular disease and the mortality rate. In contrast, a prolonged heart rate corrected-QT (QTc) interval is associated with an increased risk of arrhythmias, sudden cardiac death and coronary artery disease. The present cross-sectional study was designed to clarify the association between the physical activity level and the QTc interval in older adults.
  
  
  METHODS
  The participants included 586 older adults (267 men and 319 women, age 71.2 ± 4.7 years) without a history of cardiovascular disease, who were taking cardioactive drugs. Electrocardiography was recorded with a standard resting 12-lead electrocardiograph, while the QTc interval was calculated according to Hodges' formula. The physical activity level was assessed using a triaxial accelerometer. The participants were divided into four categories, which were defined equally quartile distributions of the QTc interval.
  
  
  RESULTS
  After adjusting for age, body mass index, waist circumference and the number of steps, the time spent in inactivity was higher and the time spent in light physical activity was significantly lower in the longest QTc interval group than in the shortest QTc interval group in both sexes (P < 0.05, respectively). However, there were no significant differences in the time spent in moderate and vigorous physical activities among the four groups in either sex.
  
  
  CONCLUSIONS
  These results suggest that a decreased physical activity level, especially inactivity and light intensity physical activity, were associated with QTc interval in older adults.
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Ryoma
authors.initials: R
authors.lastname: Michishita
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Fukae
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Rikako
authors.initials: R
authors.lastname: Mihara
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ikenaga
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Morimura
authors.affiliation: Japan Society for the Promotion of Science, Tokyo, Japan.|Faculty of Sport Sciences, Waseda University, Saitama, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Fukuoka University Institute for Physical Activity, Fukuoka, Japan.|Department of Nutritional Science, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.|Fukuoka University Institute for Physical Activity, Fukuoka, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Higaki
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.|Fukuoka University Institute for Physical Activity, Fukuoka, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, Fukuoka, Japan.|Fukuoka University Institute for Physical Activity, Fukuoka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kiyonaga
mesh_terms: D000368:Aged; D015992:Body Mass Index; D003324:Coronary Artery Disease / Q000453:epidemiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D012307:Risk Factors
keywords: QTc interval; inactivity time; light intensity physical activity; older adults