Thigh Ischemia-Reperfusion Model Does Not Accelerate Pulmonary VO2 Kinetics at High Intensity Cycling Exercise

Abstract

Background: We aimed to investigate the effect of a priming ischemia-reperfusion (IR) model on the kinetics of pulmonary oxygen uptake (VO 2 ) and cardiopulmonary parameters after high-intensity exercise. Our primary outcome was the overall VO 2 kinetics and secondary outcomes were heart rate (HR) and O 2 pulse kinetics. We hypothesized that the IR model would accelerate VO 2 and cardiopulmonary kinetics during the exercise. Methods: 10 recreationally active men (25.7 ± 4.7 years; 79.3 ± 10.8 kg; 177 ± 5 cm; 44.5 ± 6.2 mL kg −1 min −1 ) performed a maximal incremental ramp test and four constant load sessions at the midpoint between ventilatory threshold and VO 2 max on separate days: two without IR (CON) and two with IR (IR). The IR model consisted of a thigh bi-lateral occlusion for 15 min at a pressure of 250 mmHg, followed by 3 min off, before high-intensity exercise bouts. Results: There were no significant differences for any VO 2 kinetics parameters (VO 2 base 1.08 ± 0.08 vs. 1.12 ± 0.06 L min −1 ; P = 0.30; τ = 50.1 ± 7.0 vs. 47.9 ± 6.4 s; P = 0.47), as well as for HR (MRT 180s 67.3 ± 6.0 vs. 71.3 ± 6.1 s; P = 0.54) and O 2 pulse kinetics (MRT 180s 40.9 ± 3.9 vs. 48.2 ± 5.6 s; P = 0.31) between IR and CON conditions, respectively. Conclusion: We concluded that the priming IR model used in this study had no influence on VO 2 , HR, and O 2 pulse kinetics during high-intensity cycling exercise.

Moderate-intensity exercise with blood flow restriction on cardiopulmonary kinetics and efficiency during a subsequent high-intensity exercise in young women

“…Recently, Helal et al [9] failed to demonstrate any influence of RIPC on trueV˙O 2 , HR, and O 2 pulse kinetics during a subsequent high-intensity exercise. The major difference between the studies mentioned above and the present study was that we used vascular occlusion associated with a priming moderate-intensity exercise, which has been recommended according to more recent reviews [38] .…”

“…The examiner who implemented the protocol associated with vascular occlusion was different from the one who applied the other exercises. Studies have used different rest intervals between priming and subsequent training bouts, with time periods ranging from 7 to 15 minutes [9] . We decided to use a 15-minute interval between training bouts as it was considered an adequate period to ensure a proper heart rate return to baseline before starting the high-intensity protocol in order to avoid any interference when it comes to the heart rate (HR) kinetics analysis.…”

“…Furthermore, studies have likewise suggested blood flow restriction (BFR) training or remote ischemic preconditioning (RIPC) as PE methods to optimize performance in several sports due to the resulted increase in blood flow to the limbs during a subsequent exercise, [9] with potential to reduce muscle fatigue, [10] through improvements in oxygen uptake (trueV˙O 2 ) and lower blood lactate accumulation [11] . However, reports of the favorable effects of RIPC or BFR on exercise performance [12] or kinetics [9] appear not to be consistent in the scientific literature. The benefits of RIPC on muscle oxygen kinetics are possibly linked to faster muscle deoxygenation kinetics and an increased trueV˙O 2 peak, which has been observed during both moderate and maximal exercise [13] …”

“…The rationale for applying PE with BFR is based on previous studies that demonstrated benefits from a high-intensity warm-up but not from a moderate-intensity priming activity on oxygen kinetics. Given that BFR training is considered a method to mimic high-intensity exercise using lower intensity protocols, we believe that the addition of BFR to moderate-intensity exercise can produce benefits which would otherwise be achieved only at higher loads [9] …”

“…[6] Among these factors, highintensity training implemented prior to a subsequent bout of exercise seems to increase the performance of the latter due to higher O 2 availability and acceleration. [8] Furthermore, studies have likewise suggested blood flow restriction (BFR) training or remote ischemic preconditioning (RIPC) as PE methods to optimize performance in several sports due to the resulted increase in blood flow to the limbs during a subsequent exercise, [9] with potential to reduce muscle fatigue, [10] through improvements in oxygen uptake ( _ VO 2 ) and lower blood lactate accumulation. [11] However, reports of the favorable effects of RIPC or BFR on exercise performance [12] or kinetics [9] appear not to be consistent in the scientific literature.…”