The effects of temporally increased central blood volume (CBV) on cardiorespiratory and metabolic functions during recovery periods after a dynamic arm exercise were investigated using a water immersion (WI) method. Eight males cranked a cycleergometer for 12 min using unimmersed arms at each of the 3 submaximal work intensity levels (80% and 100% of the ventilatory threshold (VT) and 100% VT level plus 40% of the difference between the VT and peak VO₂). This was followed by 12 min of resting period. VO₂, VCO₂, VE, HR and blood lactic acid concentration (LA) were measured during this recovery period. The VO₂, VCO₂ and VE differences between the WI and control conditions were dependent on work intensity and duration; the heavier the work intensity and the earlier the recovery period, the higher the VO₂, VCO₂ and VE with WI compared with the control. After 4 min of recovery, VE was lower with WI regardless of work intensity. During recovery at all work intensities, HR with WI remained lower than that for the control. The effect of WI on HR during recovery was also work-rate and time dependent; the lighter the load and the earlier the recovery period, the greater the effect of WI. An interaction effect of WI and work-rate was revealed for LA during recovery periods. At the low work-rate level, LA was lower with WI, but data were reverse on the high work-rate. It was concluded that CBV increase due to WI would accelerate the entire recovery process of cardio-respiratory and metabolic functions when work-intensity was relatively light. On the other hand, On the recovery from exercise at a relatively high work intensity, it might facilitate the ventilatory response and increase the metabolic synthesis during early phase.

DESCENTE SPORTS SCIENCE Vol.22/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE