A 2-week period of high-intensity training significantly accelerated pulmonary oxygen uptake kinetics (τ: 20.4 vs. 28.9 s; P < 0.01) and elevated fatty acid oxidation and leak respiration.
Does a short period of high-intensity interval training improve pulmonary oxygen uptake kinetics and skeletal muscle mitochondrial function in untrained male volunteers?
A 2-week high-intensity interval training program improves pulmonary oxygen uptake kinetics and selected measures of mitochondrial function in untrained men.
Absolute Event Rate: 20.4% vs 28.9%
p-value: p=< 0.01
The aim of the present study was to examine whether improvements in pulmonary oxygen uptake (V̇o2) kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age 26 ± 2 yr; mean ± SD) performed six HIT sessions (8-12 × 60 s at incremental test peak power; 271 ± 52 W) over a 2-wk period. Before and after the HIT period, V̇o2 kinetics was modeled during moderate-intensity cycling (110 ± 19 W). Mitochondrial function was assessed with high-resolution respirometry (HRR), and maximal activities of oxidative enzymes citrate synthase (CS) and cytochrome c oxidase (COX) were accordingly determined. In response to HIT, V̇o2 kinetics became faster (τ: 20.4 ± 4.4 vs. 28.9 ± 6.1 s; P < 0.01) and fatty acid oxidation (ETFP) and leak respiration (LN) both became elevated (P < 0.05). Activity of CS and COX did not increase in response to training. Both before and after the HIT period, fast V̇o2 kinetics (low τ values) was associated with large values for ETFP, electron transport system capacity (ETS), and electron flow specific to complex II (CIIP) (P < 0.05). Collectively, these findings support that selected measures of mitochondrial function obtained with HRR are important for fast V̇o2 kinetics and better markers than maximal oxidative enzyme activity in describing the speed of the V̇o2 response during moderate-intensity exercise.
Christensen et al. (Thu,) conducted a other in Untrained healthy volunteers (n=10). High-intensity training (HIT) vs. Baseline (before HIT) was evaluated on Pulmonary oxygen uptake (V̇o2) kinetics (τ) (p=< 0.01). A 2-week period of high-intensity training significantly accelerated pulmonary oxygen uptake kinetics (τ: 20.4 vs. 28.9 s; P < 0.01) and elevated fatty acid oxidation and leak respiration.
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