Effects of acute hypoxia on cerebral and muscle oxygenation during incremental exercise

2007 ◽  
Vol 103 (1) ◽  
pp. 177-183 ◽  
Author(s):  
Andrew W. Subudhi ◽  
Andrew C. Dimmen ◽  
Robert C. Roach

To determine if fatigue at maximal aerobic power output was associated with a critical decrease in cerebral oxygenation, 13 male cyclists performed incremental maximal exercise tests (25 W/min ramp) under normoxic (Norm: 21% FiO2) and acute hypoxic (Hypox: 12% FiO2) conditions. Near-infrared spectroscopy (NIRS) was used to monitor concentration (μM) changes of oxy- and deoxyhemoglobin (Δ[O2Hb], Δ[HHb]) in the left vastus lateralis muscle and frontal cerebral cortex. Changes in total Hb were calculated (Δ[THb] = Δ[O2Hb] + Δ[HHb]) and used as an index of change in regional blood volume. Repeated-measures ANOVA were performed across treatments and work rates (α = 0.05). During Norm, cerebral oxygenation rose between 25 and 75% peak power output {Powerpeak; increased (inc) Δ[O2Hb], inc. Δ[HHb], inc. Δ[THb]}, but fell from 75 to 100% Powerpeak {decreased (dec) Δ[O2Hb], inc. Δ[HHb], no change Δ[THb]}. In contrast, during Hypox, cerebral oxygenation dropped progressively across all work rates (dec. Δ[O2Hb], inc. Δ[HHb]), whereas Δ[THb] again rose up to 75% Powerpeak and remained constant thereafter. Changes in cerebral oxygenation during Hypox were larger than Norm. In muscle, oxygenation decreased progressively throughout exercise in both Norm and Hypox (dec. Δ[O2Hb], inc. Δ [HHb], inc. Δ[THb]), although Δ[O2Hb] was unchanged between 75 and 100% Powerpeak. Changes in muscle oxygenation were also greater in Hypox compared with Norm. On the basis of these findings, it is unlikely that changes in cerebral oxygenation limit incremental exercise performance in normoxia, yet it is possible that such changes play a more pivotal role in hypoxia.

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5704 ◽  
Author(s):  
Damiano Formenti ◽  
David Perpetuini ◽  
Pierpaolo Iodice ◽  
Daniela Cardone ◽  
Giovanni Michielon ◽  
...  

Background One of the mechanisms responsible for enhancing muscular hypertrophy is the high metabolic stress associated with a reduced muscular oxygenation occurring during exercise, which can be achieved by reducing the speed of movement. Studies have tested that lowered muscle oxygenation artificially induced by an inflatable cuff, could provoke changes in prefrontal cortex oxygenation, hence, to central fatigue. It was hypothesized that (1) exercising with a slow speed of movement would result in greater increase in cerebral and greater decrease in muscle oxygenation compared with exercises of faster speed and (2) the amount of oxygenation increase in the ipsilateral prefrontal cortex would be lower than the contralateral one. Methods An ISS Imagent frequency domain near infrared spectroscopy (NIRS) system was used to quantify oxygenation changes in the vastus lateralis muscle and prefrontal cortex (contra- and ipsilateral) during unilateral resistance exercises with different speeds of movement to voluntary fatigue. After one maximal repetition (1RM) test, eight subjects performed three sets of unilateral knee extensions (∼50% of 1RM), separated by 2 min rest periods, following the pace of 1 s, 3 s and 5 s for both concentric and eccentric phases, in a random order, during separate sessions. The amount of change for NIRS parameters for muscle (ΔHb: deoxyhemoglobin, ΔHbO: oxyhemoglobin, ΔHbT: total hemoglobin, ΔStO2: oxygen saturation) were quantified and compared between conditions and sets by two-way ANOVA RM. Differences in NIRS parameters between contra- and ipsilateral (lobe) prefrontal cortex and conditions were tested. Results Exercising with slow speed of movement was associated to larger muscle deoxygenation than normal speed of movement, as revealed by significant interaction (set × condition) for ΔHb (p = 0.01), and by significant main effects of condition for ΔHbO (p = 0.007) and ΔStO2 (p = 0.016). With regards to the prefrontal cortex, contralateral lobe showed larger oxygenation increase than the ipsilateral one for ΔHb, ΔHbO, ΔHbT, ΔStO2 in each set (main effect of lobe: p < 0.05). Main effects of condition were significant only in set1 for all the parameters, and significant interaction lobe × condition was found only for ΔHb in set1 (p < 0.05). Discussion These findings provided evidence that speed of movement influences the amount of muscle oxygenation. Since the lack of oxygen in muscle is associated to increased metabolic stress, manipulating the speed of movement may be useful in planning resistance-training programs. Moreover, consistent oxygenation increases in both right and left prefrontal lobes were found, suggesting a complementary interaction between the ipsi- and contralateral prefrontal cortex, which also seems related to fatigue.


2008 ◽  
Vol 294 (1) ◽  
pp. H164-H171 ◽  
Author(s):  
Andrew W. Subudhi ◽  
Matthew C. Lorenz ◽  
Charles S. Fulco ◽  
Robert C. Roach

We sought to describe cerebrovascular responses to incremental exercise and test the hypothesis that changes in cerebral oxygenation influence maximal performance. Eleven men cycled in three conditions: 1) sea level (SL); 2) acute hypoxia [AH; hypobaric chamber, inspired Po2 (PiO2) 86 Torr]; and 3) chronic hypoxia [CH; 4,300 m, PiO2 86 Torr]. At maximal work rate (Ẇmax), fraction of inspired oxygen (FiO2) was surreptitiously increased to 0.60, while subjects were encouraged to continue pedaling. Changes in cerebral (frontal lobe) (COX) and muscle (vastus lateralis) oxygenation (MOX) (near infrared spectroscopy), middle cerebral artery blood flow velocity (MCA Vmean; transcranial Doppler), and end-tidal Pco2 (PetCO2) were analyzed across %Ẇmax (significance at P < 0.05). At SL, PetCO2, MCA Vmean, and COX fell as work rate rose from 75 to 100% Ẇmax. During AH, PetCO2 and MCA Vmean declined from 50 to 100% Ẇmax, while COX fell from rest. With CH, PetCO2 and COX dropped throughout exercise, while MCA Vmean fell only from 75 to 100% Ẇmax. MOX fell from rest to 75% Ẇmax at SL and AH and throughout exercise in CH. The magnitude of fall in COX, but not MOX, was different between conditions (CH > AH > SL). FiO2 0.60 at Ẇmax did not prolong exercise at SL, yet allowed subjects to continue for 96 ± 61 s in AH and 162 ± 90 s in CH. During FiO2 0.60, COX rose and MOX remained constant as work rate increased. Thus cerebral hypoxia appeared to impose a limit to maximal exercise during hypobaric hypoxia (PiO2 86 Torr), since its reversal was associated with improved performance.


Author(s):  
Theresa Schörkmaier ◽  
Yvonne Wahl ◽  
Christian Brinkmann ◽  
Wilhelm Bloch ◽  
Patrick Wahl

AbstractRecent studies have shown that the oxygenated hemoglobin level can be enhanced during rest through the application of nonivamide-nicoboxil cream. However, the effect of nonivamide-nicoboxil cream on oxygenation and endurance performance under hypoxic conditions is unknown. Therefore, the purpose of this study was to investigate the effects of nonivamide-nicoboxil cream on local muscle oxygenation and endurance performance under normoxic and hypoxic conditions. In a cross-over design, 13 athletes (experienced cyclists or triathletes [age: 25.2±3.5 years; VO2max 62.1±7.3 mL·min−1·kg−1]) performed four incremental exercise tests on the cycle ergometer under normoxic or hypoxic conditions, either with nonivamide-nicoboxil or placebo cream. Muscle oxygenation was recorded with near-infrared spectroscopy. Capillary blood samples were taken after each step, and spirometric data were recorded continuously. The application of nonivamide-nicoboxil cream increased muscle oxygenation at rest and during different submaximal workloads as well as during physical exhaustion, irrespective of normoxic or hypoxic conditions. Overall, there were no significant effects of nonivamide-nicoboxil on peak power output, maximal oxygen uptake or lactate concentrations. Muscle oxygenation is significantly higher with the application of nonivamide-nicoboxil cream. However, its application does not increase endurance performance.


2018 ◽  
Vol 125 (2) ◽  
pp. 313-319 ◽  
Author(s):  
Danilo Iannetta ◽  
Dai Okushima ◽  
Erin Calaine Inglis ◽  
Narihiko Kondo ◽  
Juan M Murias ◽  
...  

It was recently demonstrated that an O2 extraction reserve, as assessed by the near-infrared spectroscopy (NIRS)-derived deoxygenation signal ([HHb]), exists in the superficial region of vastus lateralis (VL) muscle during an occlusion performed at the end of a ramp-incremental test. However, it is unknown whether this reserve is present and/or different in magnitude in other portions and depths of the quadriceps muscles. We tested the hypothesis that an O2 extraction reserve would exist in other regions of this muscle but is greater in deep compared with more superficial portions. Superficial (VL-s) and deep VL (VL-d) as well as superficial rectus femoris (RF-s) were monitored by a combination of low- and high-power time-resolved (TRS) NIRS. During the occlusion immediately post-ramp-incremental test there was a significant overshoot in the [HHb] signal ( P < 0.05). However, the magnitude of this increase was greater in VL-d (93.2 ± 42.9%) compared with VL-s (55.0 ± 19.6%) and RF-s (47.8 ± 14.0%) ( P < 0.05). The present study demonstrated that an O2 extraction reserve exists in different pools of active muscle fibers of the quadriceps at the end of a ramp exercise to exhaustion. The greater magnitude in the reserve observed in the deeper portion of VL, however, suggests that this portion of muscle may present a greater surplus of oxygenated blood, which is likely due to a greater population of slow-twitch fibers. These findings add to the notion that the plateau in the [HHb] signal toward the end of a ramp-incremental exercise does not indicate the upper limit of O2 extraction. NEW & NOTEWORTHY Different portions of the quadriceps muscles exhibited an untapped O2 extraction reserve during a blood flow occlusion performed at the end of a ramp-incremental exercise. In the deeper portion of the vastus lateralis muscle, this reserve was greater compared with superficial vastus lateralis and rectus femoris. These data suggest that the O2 extraction reserve may be dependent on the vascular and/or oxidative capacities of the muscles.


2013 ◽  
Vol 38 (12) ◽  
pp. 1217-1227 ◽  
Author(s):  
Adam J. Trewin ◽  
Aaron C. Petersen ◽  
Francois Billaut ◽  
Leon R. McQuade ◽  
Bernie V. McInerney ◽  
...  

We investigated the effects of N-acetylcysteine (NAC) on metabolism during fixed work rate high-intensity interval exercise (HIIE) and self-paced 10-min time-trial (TT10) performance. Nine well-trained male cyclists (V̇O2peak, 69.4 ± 5.8 mL·kg−1·min−1; peak power output (PPO), 385 ± 43 W; mean ± SD) participated in a double-blind, repeated-measures, randomised crossover trial. Two trials (NAC supplementation and placebo) were performed 7 days apart consisting of 6 × 5 min HIIE bouts at 82% PPO (316 ± 40 W) separated by 1 min at 100 W, and then after 2 min of recovery at 100 W, TT10 was performed. Expired gases, venous blood, and electromyographic (EMG) data were collected. NAC did not influence blood glutathione but decreased lipid peroxidation compared with the placebo (P < 0.05). Fat oxidation was elevated with NAC compared with the placebo during HIIE bouts 5 and 6 (9.9 ± 8.9 vs. 3.9 ± 4.8 μmol·kg−1·min−1; P < 0.05), as was blood glucose throughout HIIE (4.3 ± 0.6 vs. 3.8 ± 0.6 mmol·L−1; P < 0.05). Blood lactate was lower with NAC after TT10 (3.3 ± 1.3 vs. 4.2 ± 1.3 mmol·L−1; P < 0.05). Median EMG frequency of the vastus lateralis was lower with NAC during HIIE (79 ± 10 vs. 85 ± 10 Hz; P < 0.05), but not TT10 (82 ± 11 Hz). Finally, NAC decreased mean power output 4.9% ± 6.6% (effect size = –0.3 ± 0.4, mean ± 90% CI) during TT10 (305 ± 57 W vs. 319 ± 45 W). These data suggest that NAC alters substrate metabolism and muscle fibre type recruitment during HIIE, which is detrimental to time-trial performance.


1999 ◽  
Vol 277 (3) ◽  
pp. H1045-H1052 ◽  
Author(s):  
H. B. Nielsen ◽  
R. Boushel ◽  
P. Madsen ◽  
N. H. Secher

The combined effects of hyperventilation and arterial desaturation on cerebral oxygenation ([Formula: see text]) were determined using near-infrared spectroscopy. Eleven competitive oarsmen were evaluated during a 6-min maximal ergometer row. The study was randomized in a double-blind fashion with an inspired O2 fraction of 0.21 or 0.30 in a crossover design. During exercise with an inspired O2 fraction of 0.21, the arterial CO2 pressure (35 ± 1 mmHg; mean ± SE) and O2 pressure (77 ± 2 mmHg) as well as the hemoglobin saturation (91.9 ± 0.7%) were reduced ( P < 0.05).[Formula: see text] was reduced from 80 ± 2 to 63 ± 2% ( P < 0.05), and the near-infrared spectroscopy-determined concentration changes in deoxy- (ΔHb) and oxyhemoglobin (ΔHbO2) of the vastus lateralis muscle increased 22 ± 3 μM and decreased 14 ± 3 μM, respectively ( P < 0.05). Increasing the inspired O2fraction to 0.30 did not affect ventilation (174 ± 4 l/min), but arterial CO2 pressure (37 ± 2 mmHg), O2 pressure (165 ± 5 mmHg), and hemoglobin O2saturation (99 ± 0.1%) increased ( P < 0.05).[Formula: see text] remained close to the resting level during exercise (79 ± 2 vs. 81 ± 2%), and although the muscle ΔHb (18 ± 2 μM) and ΔHbO2 (−12 ± 3 μM) were similar to those established without O2 supplementation, work capacity increased from 389 ± 11 to 413 ± 10 W ( P < 0.05). These results indicate that an elevated inspiratory O2fraction increases exercise performance related to maintained cerebral oxygenation rather than to an effect on the working muscles.


2016 ◽  
Vol 311 (2) ◽  
pp. H453-H464 ◽  
Author(s):  
Michail E. Keramidas ◽  
Roger Kölegård ◽  
Igor B. Mekjavic ◽  
Ola Eiken

The study examined the effects of hypoxia and horizontal bed rest, separately and in combination, on peak oxygen uptake (V̇o2 peak) during upright cycle ergometry. Ten male lowlanders underwent three 21-day confinement periods in a counterbalanced order: 1) normoxic bed rest [NBR; partial pressure of inspired O2(PiO2) = 133.1 ± 0.3 mmHg]; 2) hypoxic bed rest (HBR; PiO2= 90.0 ± 0.4 mmHg), and 3) hypoxic ambulation (HAMB; PiO2= 90.0 ± 0.4 mmHg). Before and after each confinement, subjects performed two incremental-load trials to exhaustion, while inspiring either room air (AIR), or a hypoxic gas (HYPO; PiO2= 90.0 ± 0.4 mmHg). Changes in regional oxygenation of the vastus lateralis muscle and the frontal cerebral cortex were monitored with near-infrared spectroscopy. Cardiac output (CO) was recorded using a bioimpedance method. The AIR V̇o2 peakwas decreased by both HBR (∼13.5%; P ≤ 0.001) and NBR (∼8.6%; P ≤ 0.001), with greater drop after HBR ( P = 0.01). The HYPO V̇o2 peakwas also reduced by HBR (−9.7%; P ≤ 0.001) and NBR (−6.1%; P ≤ 0.001). Peak CO was lower after both bed-rest interventions, and especially after HBR (HBR: ∼13%, NBR: ∼7%; P ≤ 0.05). Exercise-induced alterations in muscle and cerebral oxygenation were blunted in a similar manner after both bed-rest confinements. No changes were observed in HAMB. Hence, the bed-rest-induced decrease in V̇o2 peakwas exaggerated by hypoxia, most likely due to a reduction in convective O2transport, as indicated by the lower peak values of CO.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chihiro Kojima ◽  
Keiichi Yamaguchi ◽  
Hiroto Ito ◽  
Nobukazu Kasai ◽  
Olivier Girard ◽  
...  

PurposeThis study aimed to examine the effect of applying BFR during rest periods of repeated cycling sprints on muscle oxygenation.MethodsSeven active males performed 5 × 10-s maximal pedaling efforts with 40-s passive rest, with or without BFR application during rest period. BFR was applied for 30 s between sprints (between 5 and 35 s into rest) through a pneumatic pressure cuff inflated at 140 mmHg. Vastus lateralis muscle oxygenation was monitored using near-infrared spectroscopy. In addition, blood lactate concentration and heart rate were also evaluated.ResultsThe BFR trial showed significantly lower oxyhemoglobin (oxy-Hb) and tissue saturation (StO2) levels than the CON trial (P &lt; 0.05). However, power output and blood lactate concentration did not significantly differ between the two trials (P &gt; 0.05).ConclusionApplying BFR during rest periods of repeated cycling sprints decreased muscle oxygenation of active musculature, without interfering with power output during sprints.


2018 ◽  
Vol 13 (10) ◽  
pp. 1299-1307 ◽  
Author(s):  
Myriam Paquette ◽  
François Bieuzen ◽  
François Billaut

Purpose: To characterize the relationships between muscle oxygenation and performance during on- and off-water tests in highly trained sprint canoe–kayak athletes. Methods: A total of 30 athletes (19 kayakers and 11 canoeists) performed a maximal incremental test on a canoe or kayak ergometer for determination of VO2max and examination of the relation between peak power output (PPO) and physiological parameters. A subset of 21 athletes also performed a 200- and a 500- (for women) or 1000-m (for men) on-water time trial (TT). Near-infrared spectroscopy monitors were placed on the latissimus dorsi, biceps brachii, and vastus lateralis during all tests to assess changes in muscle O2 saturation (SmO2) and deoxyhemoglobin concentration ([HHb]). The minimum O2 oxygenation (SmO2min) and maximal O2 (Δ[HHb] extraction) were calculated for all subjects. Results: PPO was most strongly correlated with VO2max (R = .9), but there was also a large correlation between PPO and both SmO2min and Δ[HHb] in latissimus dorsi (R = −.5, R = .6) and vastus lateralis (R = −.6, R = .6, all P < .05). Multiple regression showed that 90% of the variance in 200-m performance was explained by both Δ[HHb] and SmO2min in the 3 muscles combined (P < .01) and 71% of the variance in 500-/1000-m performance was explained by Δ[HHb] in the 3 muscles (P < .01). This suggests that O2 extraction is a better predictor of performance than VO2max in sprint canoe–kayak. Conclusions: These results highlight the importance of peripheral adaptations in both short and long events and stress the relevance of adding muscle oxygenation measurements during testing and racing in sprint canoe–kayak.


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