David J Lim1, Jae J Kim1, Greg D Marsh1, Glen R Belfry2. 1. School of Kinesiology, Faculty of Health Sciences, Canadian Center for Activity and Aging, University of Western Ontario, 1151 Richmond Street, London, ON, Canada. 2. School of Kinesiology, Faculty of Health Sciences, Canadian Center for Activity and Aging, University of Western Ontario, 1151 Richmond Street, London, ON, Canada. gbelfry@uwo.ca.
Abstract
PURPOSE: The purpose was to compare the singular and combined effects of 5 s breath holds (BH) and 5 s sprints, every 30 s, during continuous high-intensity exercise, on ventilation ([Formula: see text]), oxygen uptake ([Formula: see text]O2) and associated kinetics (τ), carbon dioxide production ([Formula: see text]CO2), and arterialized-capillary lactate concentration ([La-]). METHODS: Ten men (24 ± 3 years) performed 4-6 min ergometer protocols that included a step-transition from 20 W to a power output of 50% of the difference between lactate threshold and [Formula: see text]O2 peak (Δ50%) including: (1) a continuous protocol (CONT) with free breathing, (2) an intermittent BH protocol (CONT-BH); repeated cycles of 5 s BH: 25 s free breathing, (3) a Fartlek protocol (Fartlek); repeated 5 s at peak aerobic power output: 25 s at Δ50%; (4) combining the 5 s Fartlek and CONT-BH protocol (Fartlek-BH). Breath-by-breath gas exchange, measured by mass spectrometry and turbine, was recorded. RESULTS: [Formula: see text] E (L min-1) was greater (p < 0.05) than CONT (90 ± 7) in all conditions CONT-BH (98 ± 16), Fartlek (105 ± 10), and Fartlek-BH (101 ± 19). [Formula: see text]O2 and [Formula: see text]CO2 (L min-1) were unchanged in CONT-BH (2.73 ± 0.14 and 3.16 ± 0.38) and greater in Fartlek (2.85 ± 0.12 and 3.43 ± 0.16), compared to CONT (2.71 ± 0.12 and 3.12 ± 0.13). Whereas, [Formula: see text]CO2 during Fartlek-BH was higher (3.28 ± 0.35) and [Formula: see text]O2 was unchanged (2.73 ± 0.14). Fartlek-BH resulted in slower [Formula: see text]O2 kinetics (62.2 ± 19 s) and greater blood lactate concentrations (11.5 ± 2.7 mM), compared to CONT (48.8 ± 12 s; 9.0 ± 2.3 mM, respectively). CONCLUSIONS: It was demonstrated that the CONT-BH resulted in increased ventilation that sustained [Formula: see text]O2. However, [Formula: see text]O2 was restricted when an additional work was combined with the BH condition.
PURPOSE: The purpose was to compare the singular and combined effects of 5 s breath holds (BH) and 5 s sprints, every 30 s, during continuous high-intensity exercise, on ventilation ([Formula: see text]), oxygen uptake ([Formula: see text]O2) and associated kinetics (τ), carbon dioxide production ([Formula: see text]CO2), and arterialized-capillary lactate concentration ([La-]). METHODS: Ten men (24 ± 3 years) performed 4-6 min ergometer protocols that included a step-transition from 20 W to a power output of 50% of the difference between lactate threshold and [Formula: see text]O2 peak (Δ50%) including: (1) a continuous protocol (CONT) with free breathing, (2) an intermittent BH protocol (CONT-BH); repeated cycles of 5 s BH: 25 s free breathing, (3) a Fartlek protocol (Fartlek); repeated 5 s at peak aerobic power output: 25 s at Δ50%; (4) combining the 5 s Fartlek and CONT-BH protocol (Fartlek-BH). Breath-by-breath gas exchange, measured by mass spectrometry and turbine, was recorded. RESULTS: [Formula: see text] E (L min-1) was greater (p < 0.05) than CONT (90 ± 7) in all conditions CONT-BH (98 ± 16), Fartlek (105 ± 10), and Fartlek-BH (101 ± 19). [Formula: see text]O2 and [Formula: see text]CO2 (L min-1) were unchanged in CONT-BH (2.73 ± 0.14 and 3.16 ± 0.38) and greater in Fartlek (2.85 ± 0.12 and 3.43 ± 0.16), compared to CONT (2.71 ± 0.12 and 3.12 ± 0.13). Whereas, [Formula: see text]CO2 during Fartlek-BH was higher (3.28 ± 0.35) and [Formula: see text]O2 was unchanged (2.73 ± 0.14). Fartlek-BH resulted in slower [Formula: see text]O2 kinetics (62.2 ± 19 s) and greater blood lactate concentrations (11.5 ± 2.7 mM), compared to CONT (48.8 ± 12 s; 9.0 ± 2.3 mM, respectively). CONCLUSIONS: It was demonstrated that the CONT-BH resulted in increased ventilation that sustained [Formula: see text]O2. However, [Formula: see text]O2 was restricted when an additional work was combined with the BH condition.
Authors: Glen R Belfry; Graydon H Raymer; Gregory D Marsh; Donald H Paterson; R Terry Thompson; Scott G Thomas Journal: J Appl Physiol (1985) Date: 2012-05-17
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