Is peak oxygen uptake a determinant of moderate-duration self-paced exercise performance in the heat?

2011 ◽  
Vol 36 (6) ◽  
pp. 863-872 ◽  
Author(s):  
Zachary J. Schlader ◽  
Stephen R. Stannard ◽  
Toby Mündel
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Skin Temperature ◽  
Exercise Performance ◽  
Perceived Exertion ◽  
Peak Oxygen Uptake ◽  
Performance Outcomes ◽  
Peak Exercise ◽  
Thermal Discomfort ◽  
Male Subjects

This study aimed to identify whether reductions in peak oxygen uptake (VO2peak) dictate performance outcomes during 30 min of self-paced exercise in the heat, which is expected to induce minimal hyperthermia. On 4 occasions, 11 male subjects completed peak and self-paced exercise in both hot (HOT, 40.2 ± 0.3 °C) and moderate (MOD; 20.4 ± 0.7 °C) conditions. During peak exercise, submaximal oxygen uptake (VO2) was ∼8% higher in HOT, but VO2peak (MOD, 4.64 ± 0.83 L·min–1; HOT, 4.54 ± 0.77 L·min–1) and peak cardiac output (Qpeak) were similar. Self-paced exercise performance was reduced by ∼21% in HOT. VO2 was similar through 15 min, but lower in HOT thereafter. Relative to MOD, this represented a higher and lower %VO2peak during the initial and latter stages. Cardiac output was similar in both trials (MOD, 31.6 ± 6.6 L·min–1; HOT, 30.1 ± 6.0 L·min–1), representing a similar percentage of Qpeak throughout. Rectal temperature was similar in both conditions until 30 min (MOD, 38.5 ± 0.3 °C; HOT, 38.7 ± 0.3 °C), while skin temperature was higher throughout in HOT (mean: MOD, 32.4 ± 1.1 °C; HOT, 37.3 ± 0.4 °C). Perceived exertion rose similarly in both conditions, while thermal discomfort was higher in HOT. These data indicate that when only skin temperature is elevated, reductions in exercise performance during moderate-duration self-paced exercise are not associated with changes in VO2peak. Rather, increases in VO2 at a given submaximal external workload and (or) thermal discomfort appear to play a larger role.

Differential effects of age and type 2 diabetes on dynamic vs. peak response of pulmonary oxygen uptake during exercise

2015 ◽  
Vol 118 (8) ◽  
pp. 1031-1039 ◽  
Author(s):  
Eamonn O'Connor ◽  
Simon Green ◽  
Catherine Kiely ◽  
Donal O'Shea ◽  
Mikel Egaña
Keyword(s):  
Type 2 Diabetes ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Older Men ◽  
Peak Oxygen Uptake ◽  
Peak Exercise ◽  
Middle Aged ◽  
Vascular Conductance

We investigated if the magnitude of the type 2 diabetes (T2D)-induced impairments in peak oxygen uptake (V̇o2) and V̇o2 kinetics was affected by age. Thirty-three men with T2D (15 middle-aged, 18 older), and 21 nondiabetic (ND) men (11 middle-aged, 10 older) matched by age were recruited. Participants completed four 6-min bouts of constant-load cycling at 80% ventilatory threshold for the determination of V̇o2 kinetics. Cardiac output (inert-gas rebreathing) was recorded at rest and 30 and 240 s during two additional bouts. Peak V̇o2 (determined from a separate graded test) was significantly ( P < 0.05) reduced in middle-aged and older men with T2D compared with their respective ND counterparts (middle-aged, 3.2 ± 0.5 vs. 2.5 ± 0.5 l/min; older, 2.7 ± 0.4 vs. 2.4 ± 0.4 l/min), and the magnitude of these impairments was not affected by age. However, the time constant of phase II of the V̇o2 response was only slowed ( P < 0.05) in middle-aged men with T2D compared with healthy counterparts, whereas it was similar among older men with and without T2D (middle-aged, 26.8 ± 9.3 vs. 41.6 ± 12.1 s; older, 40.5 ± 7.8 vs. 41.1 ± 8.5 s). Similarly, the “gains” in systemic vascular conductance (estimated from the slope between cardiac output and mean arterial pressure responses) were lower ( P < 0.05) in middle-aged men with T2D than ND controls, but similar between the older groups. The results suggest that the mechanisms by which T2D induces significant reductions in peak exercise performance are linked to a slower dynamic response of V̇o2 and reduced systemic vascular conductance responses in middle-aged men, whereas this is not the case in older men.

scholarly journals Exercise performance after salbutamol inhalation in non-asthmatic, non-athlete individuals: a randomised, controlled, cross-over trial

2018 ◽  
Vol 4 (1) ◽  
pp. e000397 ◽  
Author(s):  
Filip Eckerström ◽  
Christian Emil Rex ◽  
Marie Maagaard ◽  
Sune Rubak ◽  
Vibeke Elisabeth Hjortdal ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Minute Ventilation ◽  
Cardiopulmonary Exercise Testing ◽  
Peak Oxygen Uptake ◽  
Forced Expiratory Volume ◽  
Peak Exercise ◽  
Breath Rate ◽  
Randomised Controlled

BackgroundAsthma is a frequent diagnosis in competitive sports, and inhaled β2-agonists are commonly used by athletes. Although inhaled β2-agonists do not seem to improve performance in athletes, it has remained uncertain whether they can increase exercise performance in non-athletes.ObjectiveTo investigate the effect of inhaled β2-agonists on exercise performance in healthy non-athlete individuals.MethodsIn a double-blinded, placebo-controlled, cross-over trial, healthy, non-asthmatic, non-athlete individuals were randomised to inhalation of either 900 µg of salbutamol or placebo. Cardiopulmonary exercise testing, dynamic spirometry and impulse oscillometry were performed. The primary outcome was the effect from salbutamol on peak oxygen uptake, whereas secondary outcomes were breathing reserve and ventilation efficiency, and workload, heart rate, breath rate and minute ventilation at peak exercise under influence of salbutamol.ResultsA total of 36 healthy subjects with a mean age of 26±5 years were included. Salbutamol had no effect on peak oxygen uptake compared with placebo, 46.8±1.3 mL/kg/min versus 46.6±1.2 mL/kg/min, p=0.64. Salbutamol had no effect on workload, p=0.20, heart rate, p=0.23, breath rate, p=0.10, or minute ventilation, p=0.26, at peak exercise compared with placebo. Salbutamol lowered oxygen uptake, p=0.04, and workload, p=0.04, at anaerobic threshold compared with placebo. Forced expiratory volume in 1 s, 116%±13% of predicted, and peak expiratory flow, 122%±16% of predicted, increased after inhalation of salbutamol compared with placebo; 109%±13% and 117%±17%, respectively, p<0.01. Breathing reserve was found to be higher, 22%±2%, after salbutamol inhalation than after placebo, 16%±2%, p<0.01.ConclusionInhaled salbutamol did not improve peak oxygen uptake in healthy, non-asthmatic, non-athlete individuals compared with placebo.Trial registration numberNCT02914652.

Abstract 16900: Exertional Hemodynamics Among Patients With HFrEF Based on Resting HF Profile

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Cole Buchanan ◽  
Ashley Pratt-Cordova ◽  
Gregory Coe ◽  
Larry A Allen ◽  
Eugene E Wolfel ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Cardiac Index ◽  
Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Peak Oxygen Uptake ◽  
Peak Exercise ◽  
Pulmonary Capillary ◽  
Pulmonary Arterial ◽  
Wedge Pressure ◽  
Calorimetry Data

Introduction: HFrEF can be classified by profiles A, B, C or L based on resting pulmonary capillary wedge pressure (PCWP) and cardiac output (Qc). We characterized exertional hemodynamics by HF profile. Methods: HFrEF patients (N=34) completed invasive exercise testing with Swan-Ganz and radial arterial catheterization on upright bicycle. Oxygen uptake was monitored by indirect calorimetry. Data were recorded at supine and upright rest, two exercise stages below ventilatory threshold (steady states 1 and 2), and peak exercise. Participants were stratified into HF profiles based on supine resting hemodynamics including PCWP and cardiac index (CI): Profile A (warm-dry) PCWP≤16mmHg, CI≥2.5L/min/m 2 ; Profile B (warm-wet) PCWP>16mmHg; CI≥2.5L/min/m 2 ; Profile C (cold-wet) PCWP>16mmHg; CI<2.5L/min/m 2 ; Profile L (cold-dry) PCWP≤16mmHg, CI<2.5L/min/m 2 . Results: Demographics are displayed in the table . Peak oxygen uptake (VO 2 ) was severely reduced in all participants ( figure 1 ). Throughout exercise, profile C and L patients had lower stroke volume and Qc, but higher (A-V)O2 difference than profiles A and B ( figure 2 ). Profile B and C patients had higher resting and exertional pulmonary arterial and PCWP filling pressures compared to profiles A and L. Conclusion: Exercise performance among HFrEF patients is not uniform. Exertional hemodynamics vary substantially based on HF profile.

scholarly journals Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

2021 ◽  
Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Double Poling ◽  
Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

scholarly journals Effects of Pre-Exercise High and Low Glycaemic Meal on Intermittent Sprint and Endurance Exercise Performance

Sports ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 188 ◽  
Author(s):  
Man Tong Chua ◽  
Govindasamy Balasekaran ◽  
Mohammed Ihsan ◽  
Abdul Rashid Aziz
Keyword(s):  
Endurance Exercise ◽  
Exercise Performance ◽  
Perceived Exertion ◽  
Endurance Performance ◽  
Random Order ◽  
Glycaemic Index ◽  
Performance Outcomes ◽  
Exercise Heart Rate ◽  
Significant Difference ◽  
Varsity Athletes

The purpose of this study is to investigate the effects of ingesting either a high glycaemic index (HGI) or low glycaemic index (LGI) carbohydrate meal (preceding a 12 h overnight fast and where the meal was ingested 45-min prior to activity) on intermittent sprint and endurance exercise performance. Ten male varsity athletes from intermittent sports (age 23.6 ± 1.7 years, VO2max 51.9 ± 4.7 mL·kg−1·min−1) underwent a peak velocity (Vpeak) test and familiarisation session, followed by two experimental sessions in random order. Experimental sessions involved the ingestion of either an HGI or LGI meal, followed by the completion of the modified Loughborough Intermittent Shuttle Test (mLIST). There was no significant difference between HGI or LGI meals on sprint times (p = 0.62) and distance to exhaustion (p = 0.54) in the mLIST. Exercise heart rate, blood lactate and ratings of perceived exertion were also similar between the two meal trials throughout the mLIST (all p > 0.05). Subjective ratings of hunger, fullness, satiety and satisfaction were also not significantly different between the two meals. In conclusion, consuming either an HGI or LGI meal after a prolonged 12 h fast and ingesting the meal 45 min prior to exercise did not differ in either physiological, subjective and intermittent sprint and endurance performance outcomes.

Prediction of peak oxygen uptake from sub-maximal ratings of perceived exertion elicited during a graded exercise test in obese women

2009 ◽  
Vol 46 (6) ◽  
pp. 1150-1153 ◽  
Author(s):  
Jeremy B. J. Coquart ◽  
Christine Lemaire ◽  
Alain-Eric Dubart ◽  
Claire Douillard ◽  
David-Pol Luttenbacher ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Test ◽  
Perceived Exertion ◽  
Peak Oxygen Uptake ◽  
Obese Women ◽  
Ratings Of Perceived Exertion ◽  
Graded Exercise Test ◽  
Graded Exercise

Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat

2010 ◽  
Vol 35 (6) ◽  
pp. 834-841 ◽  
Author(s):  
Boguslaw Wilk ◽  
Brian W. Timmons ◽  
Oded Bar-Or
Keyword(s):  
Body Weight ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Fluid Intake ◽  
Tap Water ◽  
Peak Oxygen Uptake ◽  
Adolescent Male ◽  
Aerobic Performance ◽  
Hydration Status ◽  
Time To Exhaustion

We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg–1·min–1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%–65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L–1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (–0.45% ± 0.68% body weight in W, –0.66% ± 0.50% body weight in FW, and –0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance.

Physiological Correlates of Simulated Wheelchair Racing in Trained Quadriplegics

1995 ◽  
Vol 20 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Yagesh N. Bhambhani ◽  
Robert S. Burnham ◽  
Gary D. Wheeler ◽  
Peter Eriksson ◽  
Leona J. Holland ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Peak Oxygen Uptake ◽  
Peak Heart Rate ◽  
Descriptive Data ◽  
Key Words Oxygen Uptake ◽  
Factors Associated ◽  
Carbon Dioxide Rebreathing ◽  
Cord Injury ◽  
Lesion Level

This study examined the physiological responses during a 7.5-km simulated wheelchair race (SR) performed on rollers by 8 male quadriplegic marathon racers and analyzed the factors associated with SR time. Cardiac output (Q) was estimated during the SR using carbon dioxide rebreathing, from which stroke volume (SV) and [Formula: see text] were calculated. Subjects raced at 90 and 93% of peak oxygen uptake [Formula: see text] and peak heart rate, respectively. SR time was inversely related (p < 0.05) to peak [Formula: see text], and [Formula: see text], Q, and SV during the SR, but not [Formula: see text], age, and lesion level. Multiple regression analysis included only absolute SR [Formula: see text] in the equation to predict SR time: Y = −29.7X + 65.9; SE = 5.8. SR [Formula: see text] was significantly (p < 0.05) related to Q and SV but not to [Formula: see text]. These descriptive data suggest that SR performance in trained male quadriplegics might be limited by central, as opposed to peripheral, factors that determine [Formula: see text]. Key words: oxygen uptake, cardiac output, spinal cord injury

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