title: Randomized controlled trial of the effects of high intensity and low-to-moderate intensity exercise on physical fitness and fatigue in cancer survivors: results of the Resistance and Endurance exercise After ChemoTherapy (REACT) study.
abstract: BACKGROUND
  International evidence-based guidelines recommend physical exercise to form part of standard care for all cancer survivors. However, at present, the optimum exercise intensity is unclear. Therefore, we aimed to evaluate the effectiveness of a high intensity (HI) and low-to-moderate intensity (LMI) resistance and endurance exercise program compared with a wait list control (WLC) group on physical fitness and fatigue in a mixed group of cancer survivors who completed primary cancer treatment, including chemotherapy.
  
  
  METHODS
  Overall, 277 cancer survivors were randomized to 12 weeks of HI exercise (n = 91), LMI exercise (n = 95), or WLC (n = 91). Both interventions were identical with respect to exercise type, duration and frequency, and only differed in intensity. Measurements were performed at baseline (4-6 weeks after primary treatment) and post-intervention. The primary outcomes were cardiorespiratory fitness (peakVO2), muscle strength (grip strength and 30-second chair-stand test), and self-reported fatigue (Multidimensional Fatigue Inventory; MFI). Secondary outcomes included health-related quality of life, physical activity, daily functioning, body composition, mood, and sleep disturbances. Multilevel linear regression analyses were performed to estimate intervention effects using an intention-to-treat principle.
  
  
  RESULTS
  In the HI and LMI groups, 74 % and 70 % of the participants attended more than 80 % of the prescribed exercise sessions, respectively (P = 0.53). HI (β = 2.2; 95 % CI, 1.2-3.1) and LMI (β = 1.3; 95 % CI, 0.3-2.3) exercise showed significantly larger improvements in peakVO2 compared to WLC. Improvements in peakVO2 were larger for HI than LMI exercise (β = 0.9; 95 % CI, -0.1 to 1.9), but the difference was not statistically significant (P = 0.08). No intervention effects were found for grip strength and the 30-second chair-stand test. HI and LMI exercise significantly reduced general and physical fatigue and reduced activity (MFI subscales) compared to WLC, with no significant differences between both interventions. Finally, compared to WLC, we found benefits in global quality of life and anxiety after HI exercise, improved physical functioning after HI and LMI exercise, and less problems at work after LMI exercise.
  
  
  CONCLUSIONS
  Shortly after completion of cancer treatment, both HI and LMI exercise were safe and effective. There may be a dose-response relationship between exercise intensity and peakVO2, favoring HI exercise. HI and LMI exercise were equally effective in reducing general and physical fatigue.
  
  
  BACKGROUND
  This study was registered at the Netherlands Trial Register [ NTR2153 ] on the 5th of January 2010.
authors.affiliation: VU University Medical Center, Department of Public & Occupational Health, and the EMGO Institute for Health and Care Research, Amsterdam, The Netherlands. c.kampshoff@vumc.nl.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Kampshoff
authors.affiliation: VU University Medical Center, Department of Public & Occupational Health, and the EMGO Institute for Health and Care Research, Amsterdam, The Netherlands. m.chinapaw@vumc.nl.
authors.forename: Mai J M
authors.initials: MJ
authors.lastname: Chinapaw
authors.affiliation: VU University Medical Center, Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands. j.brug@vumc.nl.
authors.forename: Johannes
authors.initials: J
authors.lastname: Brug
authors.affiliation: VU University Medical Center, Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands. jwr.twisk@vumc.nl.
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Twisk
authors.affiliation: Máxima Medical Center, Department of Sports Medicine, Veldhoven, The Netherlands. g.schep@mmc.nl.
authors.forename: Goof
authors.initials: G
authors.lastname: Schep
authors.affiliation: Máxima Oncology Center, Eindhoven and Veldhoven, The Netherlands. m.nijziel@mmc.nl.
authors.forename: Marten R
authors.initials: MR
authors.lastname: Nijziel
authors.affiliation: VU University Medical Center, Department of Public & Occupational Health, and the EMGO Institute for Health and Care Research, Amsterdam, The Netherlands. w.vanmechelen@vumc.nl.
authors.forename: Willem
authors.initials: W
authors.lastname: van Mechelen
authors.affiliation: VU University Medical Center, Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands. l.buffart@vumc.nl.
authors.forename: Laurien M
authors.initials: LM
authors.lastname: Buffart
mesh_terms: D015444:Exercise / Q000502:physiology*; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D010809:Physical Fitness / Q000502:physiology*; D011788:Quality of Life; D017741:Survivors