Effect of Acute Dietary Nitrate Consumption on Oxygen Consumption During Submaximal Exercise in Hypobaric Hypoxia

2016 ◽  
Vol 26 (4) ◽  
pp. 315-322 ◽  
Author(s):  
Colin R. Carriker ◽  
Christine M. Mermier ◽  
Trisha A. VanDusseldorp ◽  
Kelly E. Johnson ◽  
Nicholas M. Beltz ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Hypobaric Hypoxia ◽  
Perceived Exertion ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Crossover Fashion ◽  
Oxygen Cost ◽  
Nitrate Consumption ◽  
Nitrate Supplementation

Reduced partial pressure of oxygen impairs exercise performance at altitude. Acute nitrate supplementation, at sea level, may reduce oxygen cost during submaximal exercise in hypobaric hypoxia. Therefore, we investigated the metabolic response during exercise at altitude following acute nitrate consumption. Ten well-trained (61.0 ± 7.4 ml/kg/min) males (age 28 ± 7 yr) completed 3 experimental trials (T1, T2, T3). T1 included baseline demographics, a maximal aerobic capacity test (VO2max) and five submaximal intensity cycling determination bouts at an elevation of 1600 m. A 4-day dietary washout, minimizing consumption of nitrate-rich foods, preceded T2 and T3. In a randomized, double-blind, placebo-controlled, crossover fashion, subjects consumed either a nitrate-depleted beetroot juice (PL) or ~12.8 mmol nitrate rich (NR) beverage 2.5 hr before T2 and T3. Exercise at 3500 m (T2 and T3) via hypobaric hypoxia consisted of a 5-min warm-up (25% of normobaric (VO2max) and four 5-min cycling bouts (40, 50, 60, 70% of normobaric VO2max) each separated by a 4-min rest period. Cycling RPM and watts for each submaximal bout during T2 and T3 were determined during T1. Preexercise plasma nitrite was elevated following NR consumption compared with PL (1.4 ± 1.2 and 0.7 ± 0.3 uM respectively; p < .05). There was no difference in oxygen consumption (−0.5 ± 1.8, 0.1 ± 1.7, 0.7 ± 2.1, and 1.0 ± 3.0 ml/kg/min) at any intensity (40, 50, 60, 70% of VO2max), respectively) between NR and PL. Further, respiratory exchange ratio, oxygen saturation, heart rate and rating of perceived exertion were not different at any submaximal intensity between NR and PL either. Blood lactate, however, was reduced following NR consumption compared with PL at 40 and 60% of VO2max (p < .0.05). Our findings suggest that acute nitrate supplementation before exercise at 3500 m does not reduce oxygen cost but may reduce blood lactate accumulation at lower intensity workloads.

Does blood lactate predict the chronic adaptive response to training: A comparison of traditional and talk test prescription methods

2019 ◽  
Vol 44 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Nicholas Preobrazenski ◽  
Jacob T. Bonafiglia ◽  
Matthew W. Nelms ◽  
Simo Lu ◽  
Lauren Robins ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Exercise Training ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
Training Session ◽  
Work Rate ◽  
Small Sample ◽  
Rating Of Perceived Exertion ◽  
Peak Oxygen Consumption ◽  
Control Group

The purpose of this study was to test the hypotheses (i) that interindividual variability in acute blood lactate responses during exercise at 65% of peak work rate (WRpeak; relative WRpeak protocol (REL)) will predict variability in the chronic responses to exercise training and (ii) that exercising at an intensity that causes uncomfortable speech production (negative talk test (TT) stage (NEG)) elicits high acute blood lactate responses and large adaptations to training. Twenty-eight participants completed 4 weeks of exercise training consisting of REL (n = 14) or NEG (TT, n = 14). Fifteen additional participants were assigned to a no-exercise control group (n = 15). In REL, acute blood lactate responses during the first training session significantly predicted changes in peak oxygen consumption (r = 0.69) after training. TT resulted in consistently high acute blood lactate responses. REL and TT improved (p < 0.05) peak oxygen consumption, WRpeak, and work rate at the onset of blood lactate accumulation (WROBLA). Despite nonsignificance, small to medium between-group effect sizes for changes in peak oxygen consumption, WRpeak, and WROBLA and a higher work rate, heart rate, rating of perceived exertion, and blood lactate during training at NEG support the potential superiority of TT over REL. When exercise is prescribed using a traditional method (a fixed percentage of WRpeak; REL), acute metabolic stress may partly explain the variance in the adaptations to training. In addition, TT elicited significant increases in peak oxygen consumption, WRpeak, and WROBLA, and although our small sample size limits our ability to confidently compare training adaptations between groups, our preliminary results suggest that future investigations with larger sample sizes should assess the potential superiority of TT over REL.

scholarly journals Comparison of a Traditional Graded Exercise Protocol With a Self-Paced 1-km Test to Assess Maximal Oxygen Consumption

2020 ◽  
Vol 15 (9) ◽  
pp. 1334-1339
Author(s):  
Roland van den Tillaar ◽  
Erna von Heimburg ◽  
Guro Strøm Solli
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Body Mass ◽  
Perceived Exertion ◽  
Maximal Oxygen Consumption ◽  
Body Height ◽  
Rating Of Perceived Exertion ◽  
Men And Women ◽  
Graded Exercise ◽  
Specific Alternative

Purpose: To compare the assessment of the maximal oxygen consumption (VO2max) in a traditional graded exercise test (GXT) with a 1-km self-paced running test on a nonmotorized treadmill in men and women. Methods: A total of 24 sport-science students (12 women: age 23.7 [7.7] y, body height 1.68 [0.02] m, body mass 66.6 [4.3] kg; 12 men: 22.1 [3.1] y, body height 1.82 [0.06] m, body mass 75.6 [11.0] kg) performed a traditional GXT on a motorized treadmill and a 1-km self-paced running test on a nonmotorized treadmill. VO2max, blood lactate, heart rate, and rating of perceived exertion, together with running velocity and duration at each test, were measured. Results: The main findings of the study were that the 1-km test produced significantly higher VO2max values (53.2 [9.9] vs 51.8 [8.8] mL/kg/min ) and blood lactate concentrations (11.9 [1.8] vs 11.1 [2.2] mmol/L) than the GXT (F ≥ 4.8, P ≤ .04, η2 ≥ .18). However, after controlling for sex, these differences were only present in men (60.6 [8.1] vs 58.1 [8.0] mL/kg/min , P = .027). Peak running velocity was higher in the GXT than in the 1-km test (15.7 [2.7] vs 13.0 [2.8] km/h). Men had higher VO2max values and running velocities than women in both tests. However, men and women used approximately similar pacing strategies during the 1-km test. Conclusions: Higher VO2max values were observed in a 1-km self-paced test than in the GXT. This indicates that a 1-km running test performed on a nonmotorized treadmill could serve as a simple and sport-specific alternative for the assessment of VO2max.

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 Objective and subjective measures of exercise intensity during thermo-neutral and hot yoga

2018 ◽  
Vol 43 (4) ◽  
pp. 397-402 ◽  
Author(s):  
Corinne N. Boyd ◽  
Stephanie M. Lannan ◽  
Micah N. Zuhl ◽  
Ricardo Mora-Rodriguez ◽  
Rachael K. Nelson
Keyword(s):  
Oxygen Consumption ◽  
Light Intensity ◽  
Exercise Intensity ◽  
Perceived Exertion ◽  
Maximal Oxygen Consumption ◽  
Rating Of Perceived Exertion ◽  
Moderate Intensity ◽  
Subjective Measures ◽  
Moderate Intensity Exercise ◽  
Constant Intensity

While hot yoga has gained enormous popularity in recent years, owing in part to increased environmental challenge associated with exercise in the heat, it is not clear whether hot yoga is more vigorous than thermo-neutral yoga. Therefore, the aim of this study was to determine objective and subjective measures of exercise intensity during constant intensity yoga in a hot and thermo-neutral environment. Using a randomized, crossover design, 14 participants completed 2 identical ∼20-min yoga sessions in a hot (35.3 ± 0.8 °C; humidity: 20.5% ± 1.4%) and thermo-neutral (22.1 ± 0.2 °C; humidity: 27.8% ± 1.6%) environment. Oxygen consumption and heart rate (HR) were recorded as objective measures (percentage of maximal oxygen consumption and percentage of maximal HR (%HRmax)) and rating of perceived exertion (RPE) was recorded as a subjective measure of exercise intensity. There was no difference in exercise intensity based on percentage of maximal oxygen consumption during hot versus thermo-neutral yoga (30.9% ± 2.3% vs. 30.5% ± 1.8%, p = 0.68). However, exercise intensity was significantly higher during hot versus thermo-neutral yoga based on %HRmax (67.0% ± 2.3% vs. 60.8% ± 1.9%, p = 0.01) and RPE (12 ± 1 vs. 11 ± 1, p = 0.04). According to established exercise intensities, hot yoga was classified as light-intensity exercise based on percentage of maximal oxygen consumption but moderate-intensity exercise based on %HRmax and RPE while thermo-neutral yoga was classified as light-intensity exercise based on percentage of maximal oxygen uptake, %HRmax, and RPE. Despite the added hemodynamic stress and perception that yoga is more strenuous in a hot environment, we observed similar oxygen consumption during hot versus thermo-neutral yoga, classifying both exercise modalities as light-intensity exercise.

scholarly journals Is Rating of Perceived Exertion a Valuable Tool for Monitoring Exercise Intensity During Steady-State Conditions in Elite Endurance Athletes?

2020 ◽  
pp. 1-7
Author(s):  
Thomas Losnegard ◽  
Sondre Skarli ◽  
Joar Hansen ◽  
Stian Roterud ◽  
Ida S. Svendsen ◽  
...  
Keyword(s):  
Steady State ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
Strong Relationship ◽  
Capillary Blood ◽  
Rating Of Perceived Exertion ◽  
Endurance Athletes ◽  
Subjective Perception ◽  
Test Protocol ◽  
Exercise Mode

Purpose: Rating of perceived exertion (RPE) is a widely used tool to assess subjective perception of effort during exercise. The authors investigated between-subject variation and effect of exercise mode and sex on Borg RPE (6–20) in relation to heart rate (HR), oxygen uptake (VO2), and capillary blood lactate concentrations. Methods: A total of 160 elite endurance athletes performed a submaximal and maximal test protocol either during cycling (n = 84, 37 women) or running (n = 76, 32 women). The submaximal test consisted of 4 to 7 progressive 5-minute steps within ∼50% to 85% of maximal VO2. For each step, steady-state HR, VO2, and capillary blood lactate concentrations were assessed and RPE reported. An incremental protocol to exhaustion was used to determine maximal VO2 and peak HR to provide relative (%) HR and VO2 values at submaximal work rates. Results: A strong relationship was found between RPE and %HR, %VO2, and capillary blood lactate concentrations (r = .80–.82, all Ps < .05). The between-subject coefficient of variation (SD/mean) for %HR and %VO2 decreased linearly with increased RPE, from ∼10% to 15% at RPE 8 to ∼5% at RPE 17. Compared with cycling, running induced a systematically higher %HR and %VO2 (∼2% and 5%, respectively, P < .05) with these differences being greater at lower intensities (RPE < 13). At the same RPE, women showed a trivial, but significantly higher %HR and %VO2 than men (<1%, P < .05). Conclusions: Among elite endurance athletes, exercise mode influenced RPE at a given %HR and %VO2, with greater differences at lower exercise intensities. Athletes should manage different tools to evaluate training based on intensity and duration of workouts.

The Effects of an Associative, Dissociative, Internal, and External Focus of Attention on Running Economy

2021 ◽  
pp. 1-13
Author(s):  
Mahin Aghdaei ◽  
Alireza Farsi ◽  
Maryam Khalaji ◽  
Jared Porter
Keyword(s):  
Blood Lactate ◽  
Perceived Exertion ◽  
Maximum Velocity ◽  
Focus Of Attention ◽  
Blood Lactate Level ◽  
Running Economy ◽  
Rating Of Perceived Exertion ◽  
Breathing Frequency ◽  
External Focus ◽  
Lower Blood

Much research has been executed to investigate how altering focus of attention impacts performance and feelings of fatigue. Using a within-participant design, the present study examined how an associative and dissociative attentional in addition to an internal and external attentional dimension influenced the running economy of nonprofessional runners. Twelve women (aged 18–30 years old) ran on a treadmill at 70% of their predetermined maximum velocity. Participants ran in four counterbalanced conditions (dissociative-external, dissociative-internal, associative-external, and associative-internal). Average oxygen volume, respiration volume and breathing frequency, heart rate, blood lactate level, and Borg rating of perceived exertion were measured. Our findings revealed when participants adopted a dissociative-external focus of attention, they consumed less oxygen, had lower blood lactate, and a lower rating of perceived exertion compared with trials completed using an associative attention strategy. The findings of this study demonstrate that running economy is improved and feelings of fatigue are lowest when using a combination of a dissociative-external focus of attention.

Making the Grade: An Exploration of Incline Running on a Bodyweight-Supportive Treadmill

2020 ◽  
pp. 1-5
Author(s):  
Megan Wagner ◽  
Kevin D. Dames
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Treadmill Running ◽  
Metabolic Effects ◽  
Metabolic Demand ◽  
Experimental Conditions ◽  
Cross Sectional

Context: Bodyweight-supporting treadmills are popular rehabilitation tools for athletes recovering from impact-related injuries because they reduce ground reaction forces during running. However, the overall metabolic demand of a given running speed is also reduced, meaning athletes who return to competition after using such a device in rehabilitation may not be as fit as they had been prior to their injury. Objective: To explore the metabolic effects of adding incline during bodyweight-supported treadmill running. Design: Cross-sectional. Setting: Research laboratory. Participants: Fourteen apparently healthy, recreational runners (6 females and 8 males; 21 [3] y, 1.71 [0.08] m, 63.11 [6.86] kg). Interventions: The participants performed steady-state running trials on a bodyweight-supporting treadmill at 8.5 mph. The control condition was no incline and no bodyweight support. All experimental conditions were at 30% bodyweight support. The participants began the sequence of experimental conditions at 0% incline; this increased to 1%, and from there on, 2% incline increases were introduced until a 15% grade was reached. Repeated-measures analysis of variance was used to compare all bodyweight-support conditions against the control condition. Main Outcome Measures: Oxygen consumption, heart rate, and rating of perceived exertion. Results: Level running with 30% bodyweight support reduced oxygen consumption by 21.6% (P < .001) and heart rate by 12.0% (P < .001) compared with the control. Each 2% increase in incline with bodyweight support increased oxygen consumption by 6.4% and heart rate by 3.2% on average. A 7% incline elicited similar physiological measures as the unsupported, level condition. However, the perceived intensity of this incline with bodyweight support was greater than the unsupported condition (P < .001). Conclusions: Athletes can maintain training intensity while running on a bodyweight-supporting treadmill by introducing incline. Rehabilitation programs should rely on quantitative rather than qualitative data to drive exercise prescription in this modality.

Physiological Responses and Perceived Exertion During International Taekwondo Competition

2009 ◽  
Vol 4 (4) ◽  
pp. 485-493 ◽  
Author(s):  
Craig A. Bridge ◽  
Michelle A. Jones ◽  
Barry Drust
Keyword(s):  
Blood Lactate ◽  
Perceived Exertion ◽  
Anaerobic Metabolism ◽  
Physiological Responses ◽  
Cardiovascular Responses ◽  
Capillary Blood ◽  
Rating Of Perceived Exertion ◽  
International Level ◽  
Combat Training ◽  
Aerobic And Anaerobic

Purpose:To investigate the physiological responses and perceived exertion during international Taekwondo competition.Methods:Eight male Taekwondo black belts (mean ± SD, age 22 ± 4 y, body mass 69.4 ± 13.4 kg, height 1.82 ± 0.10 m, competition experience 9 ± 5 y) took part in an international-level Taekwondo competition. Each combat included three 2-min rounds with 30 s of recovery between each round. Heart rate (HR) was recorded at 5-s intervals during each combat. Capillary blood lactate samples were taken from the fingertip 1 min before competition, directly after each round and 1 min after competition. Competitors’ rating of perceived exertion (RPE) was recorded for each round using Borg’s 6-to-20 scale.Results:HR (round 1: 175 ± 15 to round 3: 187 ± 8 beats·min−1; P < .05), percentage of HR maximum (round 1: 89 ± 8 to round 3: 96 ± 5% HRmax; P < .05), blood lactate (round 1: 7.5 ± 1.6 to round 3: 11.9 ± 2.1 mmol·L-1; P < .05) and RPE (round 1: 11 ± 2 to round 3: 14 ± 2; P < .05; mean ± SD) increased significantly across rounds.Conclusions:International-level Taekwondo competition elicited near-maximal cardiovascular responses, high blood lactate concentrations, and increases in competitors' RPE across combat. Training should therefore include exercise bouts that sufficiently stimulate both aerobic and anaerobic metabolism.

Development of an On-Water Graded Exercise Test for Flat-Water Sprint Kayak Athletes

2019 ◽  
Vol 14 (9) ◽  
pp. 1244-1249 ◽  
Author(s):  
Chelsie E. Winchcombe ◽  
Martyn J. Binnie ◽  
Matthew M. Doyle ◽  
Cruz Hogan ◽  
Peter Peeling
Keyword(s):  
Oxygen Consumption ◽  
Exercise Test ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Intraclass Correlation ◽  
Rating Of Perceived Exertion ◽  
Stroke Rate ◽  
Repeated Measures Design ◽  
Graded Exercise Test ◽  
Graded Exercise

Purpose: To determine the reliability and validity of a power-prescribed on-water (OW) graded exercise test (GXT) for flat-water sprint kayak athletes. Methods: Nine well-trained sprint kayak athletes performed 3 GXTs in a repeated-measures design. The initial GXT was performed on a stationary kayak ergometer in the laboratory (LAB). The subsequent 2 GXTs were performed OW (OW1 and OW2) in an individual kayak. Power output (PWR), stroke rate, blood lactate, heart rate, oxygen consumption, and rating of perceived exertion were measured throughout each test. Results: Both PWR and oxygen consumption showed excellent test–retest reliability between OW1 and OW2 for all 7 stages (intraclass correlation coefficient > .90). The mean results from the 2 OW GXTs (OWAVE) were then compared with LAB, and no differences in oxygen consumption across stages were evident (P ≥ .159). PWR was higher for OWAVE than for LAB in all stages (P ≤ .021) except stage 7 (P = .070). Conversely, stroke rate was lower for OWAVE than for LAB in all stages (P < .010) except stage 2 (P = .120). Conclusions: The OW GXT appears to be a reliable test in well-trained sprint kayak athletes. Given the differences in PWR and stroke rate between the LAB and OW tests, an OW GXT may provide more specific outcomes for OW training.

scholarly journals Validating Physiological and Biomechanical Parameters during Intermittent Swimming at Speed Corresponding to Lactate Concentration of 4 mmol·L−1

Sports ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 23
Author(s):  
Gavriil G. Arsoniadis ◽  
Ioannis S. Nikitakis ◽  
Petros G. Botonis ◽  
Ioannis Malliaros ◽  
Argyris G. Toubekis
Keyword(s):  
Blood Lactate ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Constant Speed ◽  
Rating Of Perceived Exertion ◽  
Training Set ◽  
Front Crawl ◽  
Stroke Length ◽  
Biomechanical Parameters

Background: Physiological and biomechanical parameters obtained during testing need validation in a training setting. The purpose of this study was to compare parameters calculated by a 5 × 200-m test with those measured during an intermittent swimming training set performed at constant speed corresponding to blood lactate concentration of 4 mmol∙L−1 (V4). Methods: Twelve competitive swimmers performed a 5 × 200-m progressively increasing speed front crawl test. Blood lactate concentration (BL) was measured after each 200 m and V4 was calculated by interpolation. Heart rate (HR), rating of perceived exertion (RPE), stroke rate (SR) and stroke length (SL) were determined during each 200 m. Subsequently, BL, HR, SR and SL corresponding to V4 were calculated. A week later, swimmers performed a 5 × 400-m training set at constant speed corresponding to V4 and BL-5×400, HR-5×400, RPE-5×400, SR-5×400, SL-5×400 were measured. Results: BL-5×400 and RPE-5×400 were similar (p > 0.05), while HR-5×400 and SR-5×400 were increased and SL-5×400 was decreased compared to values calculated by the 5 × 200-m test (p < 0.05). Conclusion: An intermittent progressively increasing speed swimming test provides physiological information with large interindividual variability. It seems that swimmers adjust their biomechanical parameters to maintain constant speed in an aerobic endurance training set of 5 × 400-m at intensity corresponding to 4 mmol∙L−1.

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