Physiological Responses to Graded Acute Normobaric Hypoxia Using an Intermittent Walking Protocol

Richardson, Alan; Twomey, Rosie; Watt, Peter; Maxwell, Neil

doi:10.1580/07-weme-or-143.1

Cited by 11 publications

(13 citation statements)

References 35 publications

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“…The possible increase in heat with a hypoxic stress factor does not improve performance, since it does not allow an adequate use of the energy substrate, and it instead has consequences on the athletes health [ 42 ]. In addition, studies have identified that walks in normobaric hypoxia tents increase the temperature because of sweating, which generates an increase in humidity and temperature [ 43 ]. This increase in temperature prevents thermoregulation at the neural level and can influence the thermal comfort zone.…”

Section: Discussionmentioning

confidence: 99%

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Vasquez-Bonilla

Rojas-Valverde

González-Custodio

et al. 2021

JCM

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Repeated sprint in hypoxia (RSH) is used to improve supramaximal cycling capacity, but little is known about the potential differences between different systems for creating normobaric hypoxia, such as a chamber, tent, or mask. This study aimed to compare the environmental (carbon dioxide (CO2) and wet-globe bulb temperature (WGBT)), perceptual (pain, respiratory difficulty, and rate of perceived exertion (RPE)), and external (peak and mean power output) and internal (peak heart rate (HRpeak), muscle oxygen saturation (SmO2), arterial oxygen saturation (SpO2), blood lactate and glucose) workload acute effects of an RSH session when performed inside a tent versus using a mask. Twelve well-trained cyclists (age = 29 ± 9.8 years, VO2max = 70.3 ± 5.9 mL/kg/min) participated in this single-blind, randomized, crossover trial. Participants completed four sessions of three sets of five repetitions × 10 s:20 s (180 s rest between series) of all-out in different conditions: normoxia in a tent (RSNTent) and mask-on (RSNMask), and normobaric hypoxia in a tent (RSHTent) and mask-on (RSHMask). CO2 and WGBT levels increased steadily in all conditions (p < 0.01) and were lower when using a mask (RSNMask and RSHMask) than when inside a tent (RSHTent and RSNTent) (p < 0.01). RSHTent presented lower SpO2 than the other three conditions (p < 0.05), and hypoxic conditions presented lower SpO2 than normoxic ones (p < 0.05). HRpeak, RPE, blood lactate, and blood glucose increased throughout the training, as expected. RSH could lead to acute conditions such as hypoxemia, which may be exacerbated when using a tent to simulate hypoxia compared to a mask-based system.

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Section: Discussionmentioning

confidence: 99%

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Vasquez-Bonilla

Rojas-Valverde

González-Custodio

et al. 2021

JCM

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“…For example, an elevation of sympathetic activity in AMS has been suggested by Loeppky et al (2003) [16], such that peripheral blood flow and vasodilation were increased, contributing to elevated HR. Others have found increased body temperature to be strongly correlated with AMS severity [18,30]. It has been suggested that reduced convective heat loss at altitude is associated with reduced cutaneous vasodilation secondary to enhanced plasma volume loss [23].…”

Section: Temporal Change In Hr Rst During Exposurementioning

confidence: 99%

Acute Mountain Sickness, Hypoxia, Hypobaria and Exercise Duration each Affect Heart Rate

et al. 2015

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In this study, we quantified the changes in post-exercise resting heart rate (HRrst) associated with acute mountain sickness (AMS), and compared the effects of hypobaric hypoxia (HH) and normobaric hypoxia (NH) on HRrst. We also examined the modulating roles of exercise duration and exposure time on HRrst. Each subject participated in 2 of 6 conditions: normobaric normoxia (NN), NH, or HH (4 400 m altitude equivalent) combined with either 10 or 60 min of moderate cycling at the beginning of an 8-h exposure. AMS was associated with a 2 bpm higher HRrst than when not sick, after taking into account the ambient environment, exercise duration, and SpO2. In addition, HRrst was elevated in both NH and HH compared to NN with HRrst being 50% higher in HH than in NH. Participating in long duration exercise led to elevated resting HRs (0.8-1.4 bpm higher) compared with short exercise, while short exercise caused a progressive increase in HRrst over the exposure period in both NH and HH (0.77-1.2 bpm/h of exposure). This data suggests that AMS, NH, HH, exercise duration, time of exposure, and SpO2 have independent effects on HRrst. It further suggests that hypobaria exerts its own effect on HRrst in hypoxia. Thus NH and HH may not be interchangeable environments.

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“…This system controlled the altitude setting automatically by sensing oxygen, carbon dioxide, and atmospheric pressure within the chamber. CAT has been applied to various research related to exercise training, aviation, military, and altitude application ( 18 , 23 ).…”

Section: Methodsmentioning

confidence: 99%

Physiological Responses between African-American and Caucasian Males Before, During and After Normobaric Hypoxic Exercise

Feeback

Seo

Glickman

2016

Medicine & Science in Sports & Exercise

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To further elucidate physiological and cognitive performance differences between African-American (AA) and Caucasian individuals (CAU) before, during or after hypoxic and normoxic exercise. Twelve college aged (18–25) apparently healthy African-American (six volunteers) and Caucasian (six subjects) males took part in two trials consisting of normobaric normoxia and normobaric hypoxia (12% oxygen). Each subject cycled at 50% of their altitude adjusted VO2max (−26% of normoxia VO2max) for one hour after a two-hour baseline. Subjects were monitored for cerebral and arterial O2 saturation, as well as the Trail Making Test A and B (TMT) psychomotor performance. Arterial saturation proved to be significantly higher in AA (86.0±4.7) compared to CAU (79.5±4.8) during the first 60 minutes of exposure to hypoxia at rest (p=0.039), but not during exercise. However, cerebral oxygenation to the left frontal lobe was decreased near the conclusion and in 30 minutes after normoxic exercise. TMT B data revealed that CAU (79±12.7) had faster scores than the AA subjects (98±25.1) at all time points and was significantly different at the 115-minute time point of the hypoxic trial (p=0.024). The data suggests that before, during and after normobaric normoxia and hypoxia trial there is a differential response between AA and CAU in regards to arterial and cerebral oxygenation, as well as psychomotor tests.

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Physiological Responses to Graded Acute Normobaric Hypoxia Using an Intermittent Walking Protocol

Cited by 11 publications

References 35 publications

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Tent versus Mask-On Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

Acute Mountain Sickness, Hypoxia, Hypobaria and Exercise Duration each Affect Heart Rate

Physiological Responses between African-American and Caucasian Males Before, During and After Normobaric Hypoxic Exercise

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