Ventilatory threshold may be a more specific measure of aerobic capacity than peak oxygen consumption rate in persons with stroke

Temperature has a dramatic effect on the physiology of ectothermic animals, impacting most of their biology. When temperatures increase above optimal for an animal, their growth rate tends to decrease. The mechanism behind this growth rate reduction is unknown. Here, we suggest the aerobic scope protection hypothesis as a mechanistic explanation for the reduction in growth. After a meal, metabolic rate, and hence oxygen consumption rate, transiently increases in a process called specific dynamic action (SDA). At warmer temperatures, the SDA response becomes temporally compressed, leading to a higher peak oxygen consumption rate. This peak in oxygen consumption rate takes up much of the animal’s aerobic scope (the difference between maximum and resting rates of oxygen consumption), leaving little residual aerobic scope for other functions. We propose that animals will actively protect their postprandial residual aerobic scope by reducing meal sizes in order to regulate the peak SDA response. This hypothesis is consistent with the published literature and we suggest further predictions to test it.

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The Effect of Metformin on Self-Selected Exercise Intensity in Healthy, Lean Males: A Randomized, Crossover, Counterbalanced Trial

Frontiers in Endocrinology ◽

10.3389/fendo.2021.599164 ◽

2021 ◽

Vol 12 ◽

Author(s):

Nanna Skytt Pilmark ◽

Christina Petersen-Bønding ◽

Nielse Frederich Rose Holm ◽

Mette Yun Johansen ◽

Bente Klarlund Pedersen ◽

...

Keyword(s):

Oxygen Consumption ◽

Exercise Intensity ◽

Oxygen Consumption Rate ◽

Perceived Exertion ◽

Consumption Rate ◽

Exercise Bout ◽

Peak Oxygen Consumption ◽

Treatment Dose ◽

Healthy Males

IntroductionIn general, patients with type 2 diabetes have lower cardiorespiratory fitness levels and perform exercise at lower intensities compared to healthy controls. Since metformin (MET) has been shown to increase the rate of perceived exertion (RPE) during exercise with a fixed intensity, MET per se may reduce self-selected exercise intensity. The aim of this study was to assess the effect of MET on self-selected exercise intensity.MethodsHealthy males were eligible for this crossover, counterbalanced study with two treatment periods: MET and placebo (PLA), each lasting 17 days. Treatment dose was gradually increased and reached 2 g/day on treatment day 9, and continued at that level for the rest of the treatment period. The two periods were performed in randomized order. Two experimental days (A+B) were conducted on Day 15 (A) and Day 17 (B) of each period, respectively. Day A consisted of an exercise bout with self-selected exercise intensity (equal to RPE = 14–15 on the Borg Scale). Day B consisted of an exercise bout with fixed intensity (70% of VO2peak). Oxygen consumption rate was assessed continuously during both exercise bouts.ResultsFifteen males (age 23.7 ± 0.6 years, BMI 22.3 ± 2.0, VO2peak 3.5 ± 0.6 L/min) were included in the study. On Day B, RPE was higher in MET compared to PLA (14.8 ± 0.4 vs. 14.0 ± 0.3, P = 0.045). On Day A, no difference in self-selected exercise intensity measured by oxygen consumption rate (PLA 2.33 ± 0.09 L O2/min, MET 2.42 ± 0.10 L O2/min, P = 0.09) was seen between treatment periods.ConclusionsSelf-selected exercise intensity was not reduced by MET in healthy males, despite the fact that MET increased RPE during an exercise bout with fixed intensity.

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Peak Oxygen Consumption and Ventilatory Thresholds on Six Modes of Exercise

Canadian Journal of Applied Physiology ◽

10.1139/h96-008 ◽

1996 ◽

Vol 21 (2) ◽

pp. 79-89 ◽

Cited By ~ 10

Author(s):

Thomas D. Smith ◽

Tom R. Thomas ◽

Ben R. Londeree ◽

Qiang Zhang ◽

George Ziogas

Keyword(s):

Oxygen Consumption ◽

Key Words ◽

Aerobic Capacity ◽

Lactate Threshold ◽

Ventilatory Threshold ◽

Maximal Oxygen Consumption ◽

The Other ◽

Peak Oxygen Consumption ◽

Capacity Measure ◽

Post Hoc

In order to compare responses on six modes of exercise for maximal oxygen consumption [Formula: see text] and ventilatory thresholds (VT-I, VT-2), 10 male recreational exercisers (23 ± 3 yrs) completed incremental maximal tests on treadmill, stationary skier, shuffle skier, stepper, stationary cycle, and rower. After extensive habituation, [Formula: see text], VT-1, and VT-2 were determined during each maximal bout. A MANOVA followed by ANOVAs, Tukey post hoc tests, and noncentral F tests indicated that the treadmill elicited a significantly higher peak oxygen consumption than did the other modes, and the skier and stepper values were higher than the rower. [Formula: see text] at VT-1 was higher on the treadmill than cycle. The treadmill also elicited a higher [Formula: see text] at VT-2 than the shuffle skier, cycle, and rower. However, no differences were observed among modes for VT-1 and VT-2 when expressed as a percentage of [Formula: see text]. These results suggest that the treadmill elicits a higher aerobic capacity measure than other modes, but the ventilatory threshold responses [Formula: see text] are similar among modes. Key words: exercise mode, aerobic capacity, lactate threshold

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Effect of physical training on peak oxygen consumption rate and exercise-induced asthma in adult asthmatics

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365518209168043 ◽

1982 ◽

Vol 42 (1) ◽

pp. 9-13 ◽

Cited By ~ 16

Author(s):

Allan Bundgaard ◽

Thorsten Ingemann-Hansen ◽

Anders Schmidt ◽

Jens Halkjaer-Kristensen

Keyword(s):

Oxygen Consumption ◽

Physical Training ◽

Oxygen Consumption Rate ◽

Consumption Rate ◽

Peak Oxygen Consumption ◽

Exercise Induced

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Electromyographic, mechanomyographic, and metabolic responses during cycle ergometry at a constant rating of perceived exertion

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2015-0144 ◽

2015 ◽

Vol 40 (11) ◽

pp. 1178-1185 ◽

Cited By ~ 7

Author(s):

Kristen C. Cochrane ◽

Terry J. Housh ◽

Nathaniel D.M. Jenkins ◽

Haley C. Bergstrom ◽

Cory M. Smith ◽

...

Keyword(s):

Oxygen Consumption ◽

Oxygen Consumption Rate ◽

Perceived Exertion ◽

Consumption Rate ◽

Polynomial Regression ◽

Vastus Lateralis ◽

Cycle Ergometry ◽

Rating Of Perceived Exertion ◽

Peak Oxygen Consumption ◽

Mean Power

Ten subjects performed four 8-min rides (65%–80% peak oxygen consumption) to determine the physical working capacity at the OMNI rating of perceived exertion (RPE) threshold (PWCOMNI). Polynomial regression analyses were used to examine the patterns of responses for surface electromyographic (EMG) amplitude (EMG AMP), EMG mean power frequency (EMG MPF), mechanomyographic (MMG) AMP, and MMG MPF of the vastus lateralis as well as oxygen consumption rate, respiratory exchange ratio (RER), and power output (PO) were examined during a 1-h ride on a cycle ergometer at a constant RPE that corresponded to the PWCOMNI. EMG AMP and MMG MPF tracked the decreases in oxygen consumption rate, RER, and PO, while EMG MPF and MMG AMP tracked RPE. The decreases in EMG AMP and MMG MPF were likely attributable to decreases in motor unit (MU) recruitment and firing rate, while the lack of change in MMG AMP may have resulted from a balance between MU de-recruitment as PO decreased, and an increase in the ability of activated fibers to oscillate. The current findings suggested that during submaximal cycle ergometry at a constant RPE, MU de-recruitment and mechanical changes within the muscle may influence the perception of effort via feedback from group III and IV afferents.

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Transiting to depth disrupts overall dynamic body acceleration and oxygen consumption rate in freely diving Steller sea lions

Marine Ecology Progress Series ◽

10.3354/meps11943 ◽

2016 ◽

Vol 562 ◽

pp. 221-236 ◽

Cited By ~ 3

Author(s):

BL Volpov ◽

ET Goundie ◽

DAS Rosen ◽

JPY Arnould ◽

AW Trites

Keyword(s):

Oxygen Consumption ◽

Oxygen Consumption Rate ◽

Consumption Rate ◽

Steller Sea Lions ◽

Body Acceleration ◽

Sea Lions ◽

Overall Dynamic Body Acceleration

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Microbial efficiency in a meromictic reservoir

Oceanological and Hydrobiological Studies ◽

10.2478/v10009-007-0047-9 ◽

2008 ◽

Vol 37 (2) ◽

Cited By ~ 2

Author(s):

Grażyna Mazurkiewicz-Boroń ◽

Teresa Bednarz ◽

Elżbieta Wilk-Woźniak

Keyword(s):

Carbon Dioxide ◽

Oxygen Consumption ◽

Release Rate ◽

Oxygen Consumption Rate ◽

Consumption Rate ◽

Metabolic Efficiency ◽

Sulphur Compounds ◽

Carbon Dioxide Release ◽

Microbial Efficiency ◽

Ion Contents

Microbial efficiency in a meromictic reservoirIndices of microbial efficiency (expressed as oxygen consumption and carbon dioxide release) were determined in the water column of the meromictic Piaseczno Reservoir (in an opencast sulphur mine), which is rich in sulphur compounds. Phytoplankton abundances were low in both the mixolimnion (up to 15 m depth) and monimolimnion (below 15 m depth). In summer and winter, carbon dioxide release was 3-fold and 5-fold higher, respectively, in the monimolimnion than in the mixolimnion. Laboratory enrichments of the sulphur substrate of the water resulted in a decrease in oxygen consumption rate of by about 42% in mixolimnion samples, and in the carbon dioxide release rate by about 69% in monimolimnion samples. Water temperature, pH and bivalent ion contents were of major importance in shaping the microbial metabolic efficiency in the mixolimnion, whilst in the monimolimnion these relationships were not evident.

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