Rate and amplitude of adaptation to intermittent and continuous exercise in older men

Purpose: This study determined the amplitude and rate of adaptation to 10 wk of continuous (CEx) and intermittent exercise (IEx) in a group of older men when the training intensity and total amount of work completed by each exercise group were the same. Methods: Ten healthy men were assigned to either a CEx (63 +/- 1 yr) or IEx (65 +/- 1 yr) group while a further five subjects (65 +/- 1 yr) acted as nonexercising controls (CON). The three groups (CEx, IEx, and CON) were matched for age, peak oxygen uptake ((V) over dot O-2peak), and cardiac output ((Q) over dot(peak)) before commencing training. The CEx group trained for 30 min at an intensity corresponding to 70-75% (V) over dot O-2peak, and the IEx group trained for a total exercise time of 30 ruin using intermittent exercise (60-s exercise, 60-s rest) at the same absolute intensity as the CEx group (CEx 112 +/- 5W; IEx 112 +/- 5W), The exercise groups trained three times per week and completed a similar amount of work during each training session (CEx, 199 +/- 9 kJ; IEx 195 +/- 9 kJ, P = 0.67). Results: The CEx and IEx groups had similar and significant amplitude increases in peak (V) over dot O-2 ventilation ((V) over dot(Epeak)), power, (Q) over dot, and SV after training. Peak (V) over dot O-2 (Q) over dot(peak), SVpeak, and peak arteriovenous O-2 difference for the CON group were unchanged. The change in (V) over dot O-2peak peak ventilation, and peak power for CEx and IEx groups were best described by a linear model. Moreover, the CEx and IEx groups had the same rate of change in (V) over dot O-2peak (CEx: 0.02 +/- 0.00 L.min(-1).wk(-1), IEx: 0.02 +/- 0.00 L.min(-1).wk(-1), P = 0.32), (V) over dot(Epeak) (CEx: 2.0 +/- 0.2 L.min(-1).wk(-1), IEx: 1.2 +/- 0.5 L.min(-1).wk(-1), P = 0.10), and peak power (CEx: 2.6 +/- 0.4 W.wk(-1), IEx: 2.6 +/- 0.4W.wk(-1), P = 0.92). Conclusion: These results suggest that the amplitude and rate of change of select adaptations in men aged 60-70 yr are independent of the mode of training (i.e., continuous or intermittent exercise) when the absolute training intensity and the total amount of work completed were similar.