title: Exercise cardiac function in young through elderly endurance trained women.
abstract: OBJECTIVE
  To clarify the physiological reasons for the decline in aerobic power of endurance trained (ET) women with aging.
  
  
  METHODS
  Blood volume, VO2max, and exercise cardiac function were examined in 23 ET women; six age 20-29 yr, six age 40-45 yr, six age 49-54 yr, and five age 58-63 yr.
  
  
  RESULTS
  Blood volume was unchanged with aging. VO2max declined progressively at a rate of 0.51 mL x kg(-1) x min(-1) x yr(-1). During maximal exercise, there was an increase in total peripheral resistance (TPR) and a decrease in heart rate, stroke volume, and cardiac output with increasing age. At all ages, cardiac filling (diastole) was significantly faster than cardiac emptying (systole). Stroke volume did not plateau at a submaximal work rate but increased progressively to maximum.
  
  
  CONCLUSIONS
  The decline in VO2max with age in ET women is due to decreases in maximal heart rate, stroke volume and cardiac output, and the primary advantage in the exercise cardiac performance of ET women of all ages is diastolic rather than systolic function.
authors.affiliation: Kinesiology & Health Science, York University, Toronto, Ontario, Canada.
authors.forename: C G
authors.initials: CG
authors.lastname: Wiebe
authors.forename: N
authors.initials: N
authors.lastname: Gledhill
authors.forename: V K
authors.initials: VK
authors.lastname: Jamnik
authors.forename: S
authors.initials: S
authors.lastname: Ferguson
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology; D013997:Time Factors