scholarly journals Acute Hormonal Responses to High-Intensity Interval Training in Hyperoxia

2020 ◽  
Vol 73 (1) ◽  
pp. 125-134
Author(s):  
Giorgio Manferdelli ◽  
Nils Freitag ◽  
Kenji Doma ◽  
Anthony C Hackney ◽  
Hans-Georg Predel ◽  
...  

AbstractThis study aimed to compare selected hormonal responses to a single session of high intensity interval training performed with an increased fraction of inspired oxygen (hyperoxia) and under normoxic conditions. Twelve recreationally trained men (age 24 ± 3 years) performed two sessions of high intensity interval training on a cycle ergometer, in randomized order with hyperoxia (4 L·min-1 with a flowrate of 94% O2) and normoxia. Each session consisted of 5 intervals of 3 minutes at 85% of the maximal power output, interspersed by 2 min at 40% of the maximal power output. Serum cortisol, prolactin and vascular endothelial growth factor (VEGF) were assessed both before and immediately after each high intensity interval training session. Statistically significant differences in cortisol were found between hyperoxic and normoxic conditions (p = 0.011), with a significant increase in hyperoxia (61.4 ± 73.2%, p = 0.013, ES = -1.03), but not in normoxia (-1.3 ± 33.5%, p > 0.05, ES = 0.1). Prolactin increased similarly in both hyperoxia (118.1 ± 145.1%, p = 0.019, ES = -0.99) and normoxia (62.14 ± 75.43%, p = 0.005, ES = -0.5). VEGF was not statistically altered in either of the conditions. Our findings indicate that a single session of high intensity interval training in low-dose hyperoxia significantly increased cortisol concentrations in recreationally trained individuals compared to normoxia, while the difference was smaller in prolactin and diminished in VEGF concentrations.

Sports ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 10
Author(s):  
Jérémy Briand ◽  
Jonathan Tremblay ◽  
Guy Thibault

High-Intensity Interval Training (HIIT) is a time-efficient training method suggested to improve health and fitness for the clinical population, healthy subjects, and athletes. Many parameters can impact the difficulty of HIIT sessions. This study aims to highlight and explain, through logical deductions, some limitations of the Skiba and Coggan models, widely used to prescribe HIIT sessions in cycling. We simulated 6198 different HIIT training sessions leading to exhaustion, according to the Skiba and Coggan-Modified (modification of the Coggan model with the introduction of an exhaustion criterion) models, for three fictitious athlete profiles (Time-Trialist, All-Rounder, Sprinter). The simulation revealed impossible sessions (i.e., requiring athletes to surpass their maximal power output over the exercise interval duration), characterized by a few short exercise intervals, performed in the severe and extreme intensity domains, alternating with long recovery bouts. The fraction of impossible sessions depends on the athlete profile and ranges between 4.4 and 22.9% for the Skiba model and 0.6 and 3.2% for the Coggan-Modified model. For practitioners using these HIIT models, this study highlights the importance of understanding these models’ inherent limitations and mathematical assumptions to draw adequate conclusions from their use to prescribe HIIT sessions.


2016 ◽  
Vol 11 (8) ◽  
pp. 1060-1066 ◽  
Author(s):  
Thimo Wiewelhove ◽  
Christian Raeder ◽  
Tim Meyer ◽  
Michael Kellmann ◽  
Mark Pfeiffer ◽  
...  

Purpose:To investigate the effect of repeated use of active recovery during a 4-d shock microcycle with 7 high-intensity interval-training (HIT) sessions on markers of fatigue. Methods:Eight elite male junior tennis players (age 15.1 ± 1.4 y) with an international ranking between 59 and 907 (International Tennis Federation) participated in this study. After each training session, they completed 15 min of either moderate jogging (active recovery [ACT]) or passive recovery (PAS) with a crossover design, which was interrupted by a 4-mo washout period. Countermovement-jump (CMJ) height, serum concentration of creatine kinase (CK), delayed-onset muscle soreness (DOMS), and perceived recovery and stress (Short Recovery and Stress Scale) were measured 24 h before and 24 h after the training program. Results:The HIT shock microcycle induced a large decrease in CMJ performance (ACT: effect size [ES] = –1.39, P < .05; PAS: ES = –1.42, P < .05) and perceived recovery (ACT: ES = –1.79, P < .05; PAS: ES = –2.39, P < .05), as well as a moderate to large increase in CK levels (ACT: ES = 0.76, P > .05; PAS: ES = 0.81, P >.05), DOMS (ACT: ES = 2.02, P < .05; PAS: ES = 2.17, P < .05), and perceived stress (ACT: ES = 1.98, P < .05; PAS: ES = 3.06, P < .05), compared with the values before the intervention. However, no significant recovery intervention × time interactions or meaningful differences in changes were noted in any of the markers between ACT and PAS. Conclusions:Repeated use of individualized ACT, consisting of 15 min of moderate jogging, after finishing each training session during an HIT shock microcycle did not affect exercise-induced fatigue.


2020 ◽  
Vol 17 (8) ◽  
pp. 835-839
Author(s):  
Carley O’Neill ◽  
Shilpa Dogra

Background: Low- and moderate-intensity exercise training has been shown to be effective for reducing general anxiety and anxiety sensitivity among adults with asthma. Exercise frequency and intensity have been shown to play an integral role in reducing anxiety sensitivity; however, less is known about the impact of high-intensity interval training (HIIT) on anxiety in adults with asthma. Methods: A 6-week HIIT intervention was conducted with adults with asthma. Participants completed HIIT (10% peak power output for 1 min, 90% peak power output for 1 min, repeated 10 times) 3 times per week on a cycle ergometer. Preintervention and postintervention assessments included the Anxiety Sensitivity Index-3 and the Body Sensations Questionnaire. Results: Total Anxiety Sensitivity Index-3 (PRE: 17.9 [11.8]; POST 12.4 [13], P = .002, Cohen d = 0.4, n = 20) and Body Sensations Questionnaire (PRE: 2.4 [1.0]; POST: 2.0 [0.8], P = .007, Cohen d = 0.3) improved from preintervention to postintervention. Conclusion: A 6-week HIIT intervention leads to improved anxiety among adults with asthma. Future research should determine the impact of HIIT among adults with asthma with clinical anxiety.


2014 ◽  
Vol 19 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Meaghan E. Maddigan ◽  
David G. Behm ◽  
Glen R. Belfry

Context:High intensity interval training (HIIT) has been shown to improve muscle power and endurance, as well as aerobic power.Objective:To assess the effects of HIIT that utilizes resistive elastic bands to improve overhand throwing velocity.Participants:Healthy female volunteers (n = 13) ranging in age from 18–29 years.Interventions:Participants were randomly assigned to either a control group or an experimental group that exercised 3 days per week for 3 weeks. Each training session involved performance of 5 sets of 20 throwing motions against elastic band resistance, which was performed by both extremities.Main Outcome Measures:Maximal oxygen consumption was measured during performance of a graded exercise test that utilized an upper extremity cycle ergometer. A radar gun was used to assess peak throwing velocity and the extent to which throwing velocity was sustained during performance of a 20-throw endurance test.Results:After completing the training, the experimental group exhibited faster peak throwing velocity (61.6 ± 6.6 km/hr to 63.2 ± 8.6 km/hr) and a reduced fatigue index (1.18 ± 0.16 to 1.01 ± 0.02). Training also resulted in a 14% improvement in maximum oxygen consumption (1.40 ± 0.46 L/min to 1.60 ± 0.49 L/ min) and longer time to fatigue (9.99 ± 1.84 min to 11.43 ± 2.29 min).Conclusion:The high-intensity interval training program was effective for improvement of overhand throwing performance.


Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 3674
Author(s):  
Tak Hiong Wong ◽  
Alexiaa Sim ◽  
Stephen F. Burns

Dietary nitrate supplementation has shown promising ergogenic effects on endurance exercise. However, at present there is no systematic analysis evaluating the effects of acute or chronic nitrate supplementation on performance measures during high-intensity interval training (HIIT) and sprint interval training (SIT). The main aim of this systematic review and meta-analysis was to evaluate the evidence for supplementation of dietary beetroot—a common source of nitrate—to improve peak and mean power output during HIIT and SIT. A systematic literature search was carried out following PRISMA guidelines and the PICOS framework within the following databases: PubMed, ProQuest, ScienceDirect, and SPORTDiscus. Search terms used were: ((nitrate OR nitrite OR beetroot) AND (HIIT or high intensity or sprint interval or SIT) AND (performance)). A total of 17 studies were included and reviewed independently. Seven studies applied an acute supplementation strategy and ten studies applied chronic supplementation. The standardised mean difference for mean power output showed an overall trivial, non-significant effect in favour of placebo (Hedges’ g = −0.05, 95% CI −0.32 to 0.21, Z = 0.39, p = 0.69). The standardised mean difference for peak power output showed a trivial, non-significant effect in favour of the beetroot juice intervention (Hedges’ g = 0.08, 95% CI -0.14 to 0.30, Z = 0.72, p = 0.47). The present meta-analysis showed trivial statistical heterogeneity in power output, but the variation in the exercise protocols, nitrate dosage, type of beetroot products, supplementation strategy, and duration among studies restricted a firm conclusion of the effect of beetroot supplementation on HIIT performance. Our findings suggest that beetroot supplementation offers no significant improvement to peak or mean power output during HIIT or SIT. Future research could further examine the ergogenic potential by optimising the beetroot supplementation strategy in terms of dosage, timing, and type of beetroot product. The potential combined effect of other ingredients in the beetroot products should not be undermined. Finally, a chronic supplementation protocol with a higher beetroot dosage (>12.9 mmol/day for 6 days) is recommended for future HIIT and SIT study.


2020 ◽  
Vol 30 (10) ◽  
pp. 1409-1416
Author(s):  
Michael Khoury ◽  
Devin B. Phillips ◽  
Peter W. Wood ◽  
William R. Mott ◽  
Michael K. Stickland ◽  
...  

AbstractIntroduction:We evaluated the safety and feasibility of high-intensity interval training via a novel telemedicine ergometer (MedBIKE™) in children with Fontan physiology.Methods:The MedBIKE™ is a custom telemedicine ergometer, incorporating a video game platform and live feed of patient video/audio, electrocardiography, pulse oximetry, and power output, for remote medical supervision and modulation of work. There were three study phases: (I) exercise workload comparison between the MedBIKE™ and a standard cardiopulmonary exercise ergometer in 10 healthy adults. (II) In-hospital safety, feasibility, and user experience (via questionnaire) assessment of a MedBIKE™ high-intensity interval training protocol in children with Fontan physiology. (III) Eight-week home-based high-intensity interval trial programme in two participants with Fontan physiology.Results:There was good agreement in oxygen consumption during graded exercise at matched work rates between the cardiopulmonary exercise ergometer and MedBIKE™ (1.1 ± 0.5 L/minute versus 1.1 ± 0.5 L/minute, p = 0.44). Ten youth with Fontan physiology (11.5 ± 1.8 years old) completed a MedBIKE™ high-intensity interval training session with no adverse events. The participants found the MedBIKE™ to be enjoyable and easy to navigate. In two participants, the 8-week home-based protocol was tolerated well with completion of 23/24 (96%) and 24/24 (100%) of sessions, respectively, and no adverse events across the 47 sessions in total.Conclusion:The MedBIKE™ resulted in similar physiological responses as compared to a cardiopulmonary exercise test ergometer and the high-intensity interval training protocol was safe, feasible, and enjoyable in youth with Fontan physiology. A randomised-controlled trial of a home-based high-intensity interval training exercise intervention using the MedBIKE™ will next be undertaken.


2002 ◽  
Vol 27 (4) ◽  
pp. 336-348 ◽  
Author(s):  
Paul B. Laursen ◽  
Michelle A. Blanchard ◽  
David G. Jenkins

This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake [Formula: see text] the first and second ventilatory thresholds (VT1, VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists [Formula: see text] performed a ramped cycle test to determine [Formula: see text]VT1, VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 × 60 s at PPO, 120 s recovery); the [Formula: see text] test was repeated < 1 wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in [Formula: see text] for either group; however, the HIT group showed a significantly greater increase in VT1 (+22% vs. −3%), VT2 (+15% vs. −1%), and PPO (+4.3 vs. −4%) compared to controls (all P < .05). This study has demonstrated that HIT can improve VT1, VT2 and PPO, following only four HIT sessions in already highly trained cyclists. Key words: cycling, cyclists, heart rate, oxygen uptake, short-term training, ventilatory threshold


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