title: Effects of exercise training amount and intensity on peak oxygen consumption in middle-age men and women at risk for cardiovascular disease.
abstract: OBJECTIVE
  Although increasing aerobic fitness by exercise training is advocated as part of a healthy lifestyle, studies examining the different effects of intensity and amount on peak consumption (V(O2)) remain sparse.
  
  
  METHODS
  This randomized controlled trial compared the effects of three different exercise regimens differing in amount and intensity on fitness improvements.
  
  
  METHODS
  Overweight men and women with mild-to-moderate dyslipidemia were recruited.
  
  
  METHODS
  The exercise groups were as follows: (1) low amount/ moderate intensity (LAMI, n = 25), the caloric equivalent of walking 19 kilometers (km)/wk at 40 to 55% of peak V(O2); (2) low amount/high intensity (LAHI, n = 36), the equivalent of jogging 19 km/wk at 65 to 80% of peak V(O2); (3) high amount/high intensity (HAHI, n = 35), the equivalent of jogging 32 km/wk at 65 to 80% of peak V(O2); and (4) a control group (n = 37).
  
  
  RESULTS
  Peak V(O2) and time to exhaustion (TTE) were tested before and after 7 to 9 months of training. All exercise groups increased peak V(O2) and TTE compared to baseline (p < or = 0.001). Improvements in peak V(O2) were greater in the LAHI and HAHI groups compared to the control group (p < 0.02); HAHI group improvements were greater than the LAMI group (p < 0.02) and the LAHI group (p < 0.02). Increased TTE for all exercise groups was higher compared to the control group (p < 0.001)
  
  
  CONCLUSIONS
  Exercising at a level of 19 km/wk at 40 to 55% of peak V(O2) is sufficient to increase aerobic fitness levels, and increasing either exercise intensity or the amount beyond these parameters will yield additional separate and combined effects on markers of aerobic fitness. Therefore, it is appropriate to recommend mild exercise to improve fitness and reduce cardiovascular risk yet encourage higher intensities and amounts for additional benefit.
authors.affiliation: Department of Medicine, Division of Cardiology, Duke University Medical Center, Box 3022, Durham, NC 27710, USA. dusch001@mc.duke.edu
authors.forename: Brian D
authors.initials: BD
authors.lastname: Duscha
authors.forename: Cris A
authors.initials: CA
authors.lastname: Slentz
authors.forename: Johanna L
authors.initials: JL
authors.lastname: Johnson
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Houmard
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Bensimhon
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Knetzger
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000517:prevention & control / Q000628:therapy*; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000534:rehabilitation*; D010101:Oxygen Consumption; D010809:Physical Fitness; D012307:Risk Factors; D016138:Walking