Eric A Martin, Claudio L Battaglini, Beth Hands, Fiona Naumann

To examine peak volume of oxygen consumption (VO2peak) changes after a high- or low-intensity exercise intervention.
. Experimental trial comparing two randomized intervention groups with control. 
. An exercise clinic at a university in Australia.
. 87 prostate cancer survivors (aged 47-80 years) and 72 breast cancer survivors (aged 34-76 years).
. Participants enrolled in an eight-week exercise intervention (n = 84) or control (n = 75) group. Intervention participants were randomized to low-intensity (n = 44, 60%-65% VO2peak, 50%-65% of one repetition maximum [1RM]) or high-intensity (n = 40, 75%-80% VO2peak, 65%-80% 1RM) exercise groups. Participants in the control group continued usual routines. All participants were assessed at weeks 1 and 10. The intervention groups were reassessed four months postintervention for sustainability. 
. VO2peak and self-reported physical activity.
. Intervention groups improved VO2peak similarly (p = 0.083), and both more than controls (p < 0.001). The high-intensity group maintained VO2peak at follow-up, whereas the low-intensity group regressed (p = 0.021). The low-intensity group minimally changed from baseline to follow-up by 0.5 ml/kg per minute, whereas the high-intensity group significantly improved by 2.2 ml/kg per minute (p = 0.01). Intervention groups always reported similar physical activity levels. 
. Higher-intensity exercise provided more sustainable cardiorespiratory benefits than lower-intensity exercise.
. Survivors need guidance on exercise intensity, because a high volume of low-intensity exercise may not provide sustained health benefits. 
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