The effects of short recovery duration on VO2 and muscle deoxygenation during intermittent exercise

Abstract

This study compared the oxygen uptake (VO(2)) and muscle deoxygenation (∆HHb) of two intermittent protocols to responses during continuous constant load cycle exercise in males (24 year ± 2, n = 7). Subjects performed three protocols: (1) 10 s work/5 s active recovery (R), R at 20 W (INT1): (2) 10 s work/5 s R, R at moderate intensity (INT2); and (3) continuous exercise (CONT), all for 10 min, on separate days. The work rate of CONT and the 10 s work of INT1 and INT2 were set within the heavy intensity domain. VO(2) and ∆HHb data were filtered and averaged to 5 s bins. Average VO(2) (80-420 s) was highest during CONT (3.77 L/min), lower in INT2 (3.04 L/min), and lowest during INT1 (2.81 L/min), all (p < 0.05). Average ∆HHb (80-420 s) was higher during CONT (p < 0.05) than both INT exercise protocols (CONT; 25.7 ± 0.9 a.u. INT1; 16.4 ± 0.8 a.u., and INT2; 15.8 ± 0.8 a.u.). The repeated changes in metabolic rate elicited oscillations in ΔHHb in both intermittent protocols, whereas oscillations in VO(2) were only observed during INT1. The greater ΔHHb during CONT suggests a reduction in oxygen delivery compared to oxygen consumption relative to INT. The higher VO(2) for INT 2 versus INT 1 and similar ΔHHb during INT suggests an increase in oxygen delivery during INT 2. Thus the different demands of INT1, INT2, and CONT protocols elicited differing physiological responses to a similar heavy intensity power output. These intermittent exercise models seem to elicit an elevated O(2) delivery condition compared to CONT.

Oxygen Delivery and Muscle Deoxygenation during Continuous, Long- and Short-Interval Exercise

“…It should be pointed that the peripheral component of VO 2 in this study was assessed by simultaneous recordings of ΔHHb, ΔHbdiff, and global A-VO 2 using independent devices, all suggesting no effect of protocol on either muscle (ΔHHb, ΔHbdiff) or global (A-VO 2 ) oxygen extraction. Our results are in contrast with those of a recent study reporting higher average ΔHHb during a 10-min continuous exercise compared to ultra-short interval protocols (10 s work and 5 s rest) of similar exercise intensity and overall duration [4]. Thus, the differences in results may be due to protocol design, since in the previous study the continuous protocol was performed with much greater effort and physiological strain than the interval (heart rate of 162 vs. 132-142 b/min).…”

“…This is the first study to investigate muscle de-oxygenation (ΔHHb, ΔHbO 2, TSI) during typical continuous, long-interval and short-interval exercise protocols. All 3 protocols increased muscle de-oxygenation (↑ΔHHb,↓ΔHbO 2 , ↓TSI) in the exercising muscle to a great extent suggesting local hypoxia and mismatch in O 2 delivery to utilization [4]. This is in accordance with previous studies showing improved skeletal muscle oxidative capacity following training with continuous, LI and SI aerobic exercise protocols [22,34,43].…”

Muscle metabolic status and acid-base balance during 10-s work:5-s recovery intermittent and continuous exercise

“…Their small sample size (n ϭ 2) limited confidence in the conclusions. Re-cently, we extended this early work with observations of reduced VO 2 and deoxyhemoglobin saturation during the work periods of INT compared with CONT exercise performed at an identical power output (3). Furthermore, we observed greater deoxyhemoglobin saturation during CONT suggesting a reduction in oxygen delivery compared with oxygen consumption relative to INT.…”

“…It has been shown that quadriceps blood flow in single-leg knee extension ergometer exercise has been shown to be some 70% higher during moderate intensity to HI compared with two-legged cycle ergometry (34). If a similar effect were present in our singleleg plantar flexion exercise model, INT exercise may have been associated with elevated muscle and capillary blood flow and improved blood flow distribution during the initial seconds of recovery (3,14) and maintained into the subsequent 10-s work interval of INT (21,37,42). Moreover, the previous work interval, followed by the rest period of this INT exercise may speed VO 2 (2,(22)(23)(24) and [PCr] (32) kinetics in a similar manner to that observed with priming HI exercise (4,22).…”

Relationship of post-exercise muscle oxygenation and duration of cycling exercise

“…Despite this dependence, reoxygenation time is apparently not influenced by exercise intensity [ 19 , 29 ]. When Belfry et al [ 36 ] compared interval-training regimens with constant-load exercise at equal intensity, they found a better matching of O 2 delivery to O 2 utilization during exercise for the interval regimens than that in constant-load exercise. O 2 delivery during interval training was enhanced when recovery was applied in the moderate intensity domain in comparison to “low-intensity” active recovery.…”