scholarly journals Tent versus Mask-on Acute Effects during Repeated-Sprint Training in Normobaric Hypoxia and Normoxia

2021 ◽  
Vol 10 (21) ◽  
pp. 4879
Author(s):  
Aldo Vasquez-Bonilla ◽  
Daniel Rojas-Valverde ◽  
Adrián González-Custodio ◽  
Rafael Timón ◽  
Guillermo Olcina
Keyword(s):  
Oxygen Saturation ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
Arterial Oxygen Saturation ◽  
Normobaric Hypoxia ◽  
Arterial Oxygen ◽  
Sprint Training ◽  
Acute Effects ◽  
Repeated Sprint ◽  
Lower Spo2

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.

No Influence of Acute Moderate Normobaric Hypoxia on Performance and Blood Lactate Concentration Responses to Repeated Wingates

2021 ◽  
Vol 16 (1) ◽  
pp. 154-157
Author(s):  
Naoya Takei ◽  
Katsuyuki Kakinoki ◽  
Olivier Girard ◽  
Hideo Hatta
Keyword(s):  
Oxygen Saturation ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
Detrimental Effect ◽  
Arterial Oxygen Saturation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Arterial Oxygen ◽  
Ratings Of Perceived Exertion ◽  
Moderate Hypoxia

Background: Training in hypoxia versus normoxia often induces larger physiological adaptations, while this does not always translate into additional performance benefits. A possible explanation is a reduced oxygen flux, negatively affecting training intensity and/or volume (decreasing training stimulus). Repeated Wingates (RW) in normoxia is an efficient training strategy for improving both physiological parameters and exercise capacity. However, it remains unclear whether the addition of hypoxia has a detrimental effect on RW performance. Purpose: To test the hypothesis that acute moderate hypoxia exposure has no detrimental effect on RW, while both metabolic and perceptual responses would be slightly higher. Methods: On separate days, 7 male university sprinters performed 3 × 30-s Wingate efforts with 4.5-min passive recovery in either hypoxia (FiO2: 0.145) or normoxia (FiO2: 0.209). Arterial oxygen saturation was assessed before the first Wingate effort, while blood lactate concentration and ratings of perceived exertion were measured after each bout. Results: Mean (P = .92) and peak (P = .63) power outputs, total work (P = .98), and the percentage decrement score (P = .25) were similar between conditions. Arterial oxygen saturation was significantly lower in hypoxia versus normoxia (92.0% [2.8%] vs 98.1% [0.4%], P < .01), whereas blood lactate concentration (P = .78) and ratings of perceived exertion (P = .51) did not differ between conditions. Conclusion: In sprinters, acute exposure to moderate hypoxia had no detrimental effect on RW performance and associated metabolic and perceptual responses.

scholarly journals Beetroot juice does not enhance altitude running performance in well-trained athletes

2015 ◽  
Vol 40 (6) ◽  
pp. 590-595 ◽  
Author(s):  
Josh Timothy Arnold ◽  
Samuel James Oliver ◽  
Tammy Maria Lewis-Jones ◽  
Lee John Wylie ◽  
Jamie Hugo Macdonald
Keyword(s):  
Heart Rate ◽  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Time Trial ◽  
Incremental Exercise ◽  
Normobaric Hypoxia ◽  
Arterial Oxygen ◽  
Oxygen Cost ◽  
Beetroot Juice ◽  
Running Performance

We hypothesized that acute dietary nitrate (NO3–) provided as concentrated beetroot juice supplement would improve endurance running performance of well-trained runners in normobaric hypoxia. Ten male runners (mean (SD): sea level maximal oxygen uptake, 66 (7) mL·kg–1·min−1; 10 km personal best, 36 (2) min) completed incremental exercise to exhaustion at 4000 m and a 10-km treadmill time-trial at 2500 m simulated altitude on separate days after supplementation with ∼7 mmol NO3– and a placebo at 2.5 h before exercise. Oxygen cost, arterial oxygen saturation, heart rate, and ratings of perceived exertion (RPE) were determined during the incremental exercise test. Differences between treatments were determined using means [95% confidence intervals], paired sample t tests, and a probability of individual response analysis. NO3– supplementation increased plasma nitrite concentration (NO3–, 473 (226) nmol·L–1 vs. placebo, 61 (37) nmol·L–1, P < 0.001) but did not alter time to exhaustion during the incremental test (NO3–, 402 (80) s vs. placebo 393 (62) s, P = 0.5) or time to complete the 10-km time-trial (NO3–, 2862 (233) s vs. placebo, 2874 (265) s, P = 0.6). Further, no practically meaningful beneficial effect on time-trial performance was observed as the 11 [–60 to 38] s improvement was less than the a priori determined minimum important difference (51 s), and only 3 runners experienced a “likely, probable” performance improvement. NO3– also did not alter oxygen cost, arterial oxygen saturation, heart rate, or RPE. Acute dietary NO3– supplementation did not consistently enhance running performance of well-trained athletes in normobaric hypoxia.

Heart rate variability and arterial oxygen saturation response during extreme normobaric hypoxia

2015 ◽  
Vol 190 ◽  
pp. 40-45 ◽  
Author(s):  
Michal Botek ◽  
Jakub Krejčí ◽  
Stefan De Smet ◽  
Aleš Gába ◽  
Andrew J. McKune
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Normobaric Hypoxia ◽  
Arterial Oxygen

Heat Added to Repeated-Sprint Training in Hypoxia Does Not Affect Cycling Performance

2021 ◽  
pp. 1-9
Author(s):  
Myles C. Dennis ◽  
Paul S.R. Goods ◽  
Martyn J. Binnie ◽  
Olivier Girard ◽  
Karen E. Wallman ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Core Temperature ◽  
Perceived Exertion ◽  
Thermal Sensation ◽  
Rating Of Perceived Exertion ◽  
Sprint Training ◽  
Active Recovery ◽  
Repeated Sprint ◽  
Air Temperatures ◽  
Desirable Outcome

Purpose: This study aimed to assess the influence of graded air temperatures during repeated-sprint training in hypoxia (RSH) on performance and physiological responses. Methods: Ten well-trained athletes completed one familiarization and 4 experimental sessions at a simulated altitude of 3000 m (0.144 FIO2) above sea level. Air temperatures utilized across the 4 experimental sessions were 20°C, 25°C, 30°C, and 35°C (all 50% relative humidity). The participants performed 3 sets of 5 × 10 seconds “all-out” cycle sprints, with 20 seconds of active recovery between sprints and 5 minutes of active recovery between sets (recovery intensity = 120 W). Core temperature, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion, and thermal sensation were collected. Results: There were no differences between conditions for peak power, mean power, and total work in each set (P > .05). There were no condition × time interaction effects for any variables tested. The peak core temperature was highest at 30°C (38.06°C [0.31°C]). Overall, the pulse oxygen saturation was higher at 35°C than at 20°C (P < .001; d < 0.8), 25°C (P < .001; d = 1.12 ± 0.54, large), and 30°C (P < .001; d = 0.84 ± 0.53, large). Conclusion: Manipulating air temperature between 20°C and 35°C had no effect on performance or core temperature during a typical RSH session. However, the pulse oxygen saturation was preserved at 35°C, which may not be a desirable outcome for RSH interventions. The application of increased levels of ambient heat may require a different approach if augmenting the RSH stimulus is the desired outcome.

Exercise intensity typical of mountain climbing does not exacerbate acute mountain sickness in normobaric hypoxia

2012 ◽  
Vol 113 (7) ◽  
pp. 1068-1074 ◽  
Author(s):  
Kai Schommer ◽  
Moritz Hammer ◽  
Lorenz Hotz ◽  
Elmar Menold ◽  
Peter Bärtsch ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Saturation ◽  
Maximal Oxygen Uptake ◽  
Arterial Oxygen Saturation ◽  
Acute Mountain Sickness ◽  
Normobaric Hypoxia ◽  
Arterial Oxygen ◽  
Moderate Exercise ◽  
Significant Difference ◽  
Mountain Sickness

Physical exertion is thought to exacerbate acute mountain sickness (AMS). In this prospective, randomized, crossover trial, we investigated whether moderate exercise worsens AMS in normobaric hypoxia (12% oxygen, equivalent to 4,500 m). Sixteen subjects were exposed to altitude twice: once with exercise [3 × 45 min within the first 4 h on a bicycle ergometer at 50% of their altitude-specific maximal workload (maximal oxygen uptake)], and once without. AMS was evaluated by the Lake Louise score and the AMS-C score of the Environmental Symptom Questionnaire. There was no significant difference in AMS between the exposures with and without exercise, neither after 5, 8, nor 18 h (incidence: 64 and 43%; LLS: 6.5 ± 0.7 and 5.1 ± 0.8; AMS-C score: 1.2 ± 0.3 and 1.1 ± 0.3 for exercise vs. rest at 18 h; all P > 0.05). Exercise decreased capillary Po2 (from 36 ± 1 Torr at rest to 31 ± 1 Torr), capillary arterial oxygen saturation (from 72% at rest to 67 ± 2%), and cerebral oxygen saturation (from 49 ± 2% at rest to 42 ± 1%, as assessed by near-infrared spectroscopy; P < 0.05), and increased ventilation (capillary Pco2 27 ± 1 Torr; P < 0.05). After exercise, the increase in ventilation persisted for several hours and was associated with similar levels of capillary and cerebral oxygenation at the exercise and rest day. We conclude that moderate exercise at ∼50% maximal oxygen uptake does not increase AMS in normobaric hypoxia. These data do not exclude that considerably higher exercise intensities exacerbate AMS.

Physiological Dynamic Apnea Responses in Relation to Apnea Capacity in Triathletes

2017 ◽  
Vol 38 (07) ◽  
pp. 521-526 ◽  
Author(s):  
Alexandre Guimard ◽  
Houssem Zorgati ◽  
Sylvain Brulaire ◽  
Virgile Amiot ◽  
Fabrice Prieur ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Perceived Exertion ◽  
Swimming Performance ◽  
Arterial Oxygen Saturation ◽  
Rating Of Perceived Exertion ◽  
Significant Alteration ◽  
Arterial Oxygen ◽  
Maximal Heart Rate ◽  
Middle Aged ◽  
Maximal Speed

AbstractThe aim was to assess the cardiac, arterial oxygen saturation, lactate, hormonal and Borg rating of perceived exertion (RPE) responses to acute apnea in relation to apnea capacity in 18 middle-aged triathletes. Subjects were monitored while swimming two 50-m freestyle exercise trials with fins at maximal speed: with normal frequency breathing (NB) and with complete apnea (Ap); the latter was used to assess apnea capacity. The subjects with significant alteration in swimming performance inducing a time increase greater than 2.5% during Ap vs. NB were put in the group: bad apnea capacity (Bad Ap); the others, who showed no significant alteration in performance, were put in the group: Good Ap. Under apnea, both groups showed a decrease in arterial oxygen saturation (p<0.05). In Ap conditions, only Bad Ap had a significant lower maximal heart rate vs. NB (p<0.05), with lower blood lactate (p<0.05) and arm stroke frequency (p<0.01). No change in saliva hormonal concentrations was found during the experiment for both groups, whereas RPE responses were increased in the Good Ap group under Ap vs. NB conditions. In conclusion, a good apnea capacity seems to be associated with lower cardiovascular and metabolic apnea alterations in middle-aged recreationally-trained triathletes.

Rapidity of Response to Hypoxic Conditions During Exercise

2013 ◽  
Vol 8 (3) ◽  
pp. 330-335 ◽  
Author(s):  
Kayla B. Henslin Harris ◽  
Carl Foster ◽  
Jos J. de Koning ◽  
Christopher Dodge ◽  
Glenn A. Wright ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Power Output ◽  
Arterial Oxygen Saturation ◽  
Time Trial ◽  
Normobaric Hypoxia ◽  
Arterial Oxygen ◽  
Hypoxic Conditions ◽  
Late Trial ◽  
Air Control

Previous studies have found decreases in arterial oxygen saturation to be temporally linked to reductions in power output (PO) during time-trial (TT) exercise. The purpose of this study was to determine whether preexercise desaturation (estimated from pulse oximetry [SpO2]), via normobaric hypoxia, would change the pattern of PO during a TT.Purpose:The authors tested the hypothesis that the starting PO of a TT would be reduced in the EARLY trial secondary to a reduced SpO2 but would not be reduced in LATE until ~30 s after the start of the TT.Methods:Eight trained cyclists/triathletes (4 male, 4 female) performed 3 randomly ordered 3-km TTs while breathing either room air (CONTROL) or hypoxic air administered 3 min before the start of the TT (EARLY) or at the beginning of the TT (LATE).Results:There was no effect of hypoxia on PO during the first 0.3 km of either the EARLY or the LATE trial compared with CONTROL, although there was a significant decrease in pre-TT SpO2 in EARLY vs CONTROL and LATE. The time for PO to decrease was ~40 s after the start of the TT in both EARLY and LATE.Conclusions:The results support the strong effect of the preexercise template on the pattern of PO during simulated competition and suggest that reductions in SpO2 are not direct signals to decrease PO.

scholarly journals Accuracy of two pulse-oximetry measurements for INTELLiVENT-ASV in mechanically ventilated patients: a prospective observational study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinshu Katayama ◽  
Jun Shima ◽  
Ken Tonai ◽  
Kansuke Koyama ◽  
Shin Nunomiya
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Prospective Observational Study ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Arterial Blood ◽  
Ventilated Patients

AbstractRecently, maintaining a certain oxygen saturation measured by pulse oximetry (SpO2) range in mechanically ventilated patients was recommended; attaching the INTELLiVENT-ASV to ventilators might be beneficial. We evaluated the SpO2 measurement accuracy of a Nihon Kohden and a Masimo monitor compared to actual arterial oxygen saturation (SaO2). SpO2 was simultaneously measured by a Nihon Kohden and Masimo monitor in patients consecutively admitted to a general intensive care unit and mechanically ventilated. Bland–Altman plots were used to compare measured SpO2 with actual SaO2. One hundred mechanically ventilated patients and 1497 arterial blood gas results were reviewed. Mean SaO2 values, Nihon Kohden SpO2 measurements, and Masimo SpO2 measurements were 95.7%, 96.4%, and 96.9%, respectively. The Nihon Kohden SpO2 measurements were less biased than Masimo measurements; their precision was not significantly different. Nihon Kohden and Masimo SpO2 measurements were not significantly different in the “SaO2 < 94%” group (P = 0.083). In the “94% ≤ SaO2 < 98%” and “SaO2 ≥ 98%” groups, there were significant differences between the Nihon Kohden and Masimo SpO2 measurements (P < 0.0001; P = 0.006; respectively). Therefore, when using automatically controlling oxygenation with INTELLiVENT-ASV in mechanically ventilated patients, the Nihon Kohden SpO2 sensor is preferable.Trial registration UMIN000027671. Registered 7 June 2017.

scholarly journals BIOCHEMICAL STUDIES ON SHOCK

1944 ◽  
Vol 79 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Frank L. Engel ◽  
Helen C. Harrison ◽  
C. N. H. Long
Keyword(s):  
Blood Pressure ◽  
Amino Acids ◽  
Oxygen Saturation ◽  
Hepatic Artery ◽  
Arterial Oxygen Saturation ◽  
Amino Nitrogen ◽  
Arterial Oxygen ◽  
High Positive Correlation ◽  
Peripheral Tissues ◽  
Arterial Blood

1. In a series of rats subjected to hemorrhage and shock a high negative correlation was found between the portal and peripheral venous oxygen saturations and the arterial blood pressure on the one hand, and the blood amino nitrogen levels on the other, and a high positive correlation between the portal and the peripheral oxygen saturations and between each of these and the blood pressure. 2. In five cats subjected to hemorrhage and shock the rise in plasma amino nitrogen and the fall in peripheral and portal venous oxygen saturations were confirmed. Further it was shown that the hepatic vein oxygen saturation falls early in shock while the arterial oxygen saturation showed no alteration except terminally, when it may fall also. 3. Ligation of the hepatic artery in rats did not affect the liver's ability to deaminate amino acids. Hemorrhage in a series of hepatic artery ligated rats did not produce any greater rise in the blood amino nitrogen than a similar hemorrhage in normal rats. The hepatic artery probably cannot compensate to any degree for the decrease in portal blood flow in shock. 4. An operation was devised whereby the viscera and portal circulation of the rat were eliminated and the liver maintained only on its arterial circulation. The ability of such a liver to metabolize amino acids was found to be less than either the normal or the hepatic artery ligated liver and to have very little reserve. 5. On complete occlusion of the circulation to the rat liver this organ was found to resist anoxia up to 45 minutes. With further anoxia irreversible damage to this organ's ability to handle amino acids occurred. 6. It is concluded that the blood amino nitrogen rise during shock results from an increased breakdown of protein in the peripheral tissues, the products of which accumulate either because they do not circulate through the liver at a sufficiently rapid rate or because with continued anoxia intrinsic damage may occur to the hepatic parenchyma so that it cannot dispose of amino acids.

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