Physiologic responses to a thermogenic nutritional supplement at rest, during low-intensity exercise, and during recovery from exercise in college-aged women

2013 ◽  
Vol 38 (9) ◽  
pp. 988-995 ◽  
Author(s):  
Haley C. Bergstrom ◽  
Terry J. Housh ◽  
Daniel A. Traylor ◽  
Robert W. Lewis ◽  
Nathaniel D.M. Jenkins ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Perceived Exertion ◽  
Resting Energy Expenditure ◽  
Nutritional Supplement ◽  
Ratings Of Perceived Exertion ◽  
Perception Of Effort ◽  
Postexercise Recovery ◽  
Double Blinded ◽  
Low Intensity Exercise ◽  
Physiologic Responses

This study examined acute physiologic responses to a thermogenic nutritional supplement at rest, during exercise, and during recovery from exercise in women. Twelve women (mean ± SD age, 22.9 ± 3.1 years) were recruited for this randomized, double-blinded, placebo-controlled, crossover study. Each testing session consisted of 4 phases: 30 min of presupplementation resting, followed by the ingestion of the placebo or thermogenic nutritional supplement; 50 min of postsupplementation resting; 60 min of walking (at 3.2–4.8 km·h−1); and 50 min of postexercise resting. Energy expenditure (EE), oxygen consumption, respiratory exchange ratio (RER), oxygen (O2) pulse, and heart rate (HR) values were recorded during all 4 phases. Systolic (SBP) and diastolic (DBP) blood pressure were recorded during the rest, postsupplementation, and postexercise recovery phases; ratings of perceived exertion (RPE) were recorded only during exercise. There were no significant differences for EE, oxygen consumption, O2 pulse, HR, SBP, or DBP between the supplement and placebo during the presupplementation resting or postsupplementation phases. The RER, however, was higher with the supplement at 30 min postsupplementation. During exercise, EE and O2 pulse were 3%–6% greater with the supplement than placebo; there were no significant differences in RPE. Postexercise, EE, oxygen consumption, and DBP were 3%–7% greater with the supplement than placebo. These findings suggest that a thermogenic nutritional supplement, when combined with exercise, increases metabolic rate but has no effect on the perception of effort and results in only minimal changes in cardiovascular function.

Effects of erythropoietin administration on cerebral metabolism and exercise capacity in men

2010 ◽  
Vol 109 (2) ◽  
pp. 476-483 ◽  
Author(s):  
P. Rasmussen ◽  
E. M. Foged ◽  
R. Krogh-Madsen ◽  
J. Nielsen ◽  
T. R. Nielsen ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Oxygen Delivery ◽  
Perceived Exertion ◽  
Cerebral Metabolism ◽  
Central Fatigue ◽  
Voluntary Activation ◽  
High Dose ◽  
Ratings Of Perceived Exertion ◽  
Human Erythropoietin ◽  
Double Blinded

Recombinant human erythropoietin (EPO) increases exercise capacity by stimulating erythropoiesis and subsequently enhancing oxygen delivery to the working muscles. In a large dose, EPO crosses the BBB and may reduce central fatigue and improve cognition. In turn, this would augment exercise capacity independent of erythropoiesis. To test this hypothesis, 15 healthy young men (18–34 years old, 74 ± 7 kg) received either 3 days of high-dose (30,000 IU/day; n = 7) double-blinded placebo controlled or 3 mo of low-dose (5,000 IU/wk; n = 8) counter-balanced open but controlled administration of EPO. We recorded exercise capacity, transcranial ultrasonography-derived middle cerebral artery blood velocity, and arterial-internal jugular venous concentration differences of glucose and lactate. In addition, cognitive function, ratings of perceived exertion, ventilation, and voluntary activation by transcranial magnetic stimulation-induced twitch force were evaluated. Although EPO in a high dose increased cerebrospinal fluid EPO concentration ∼20-fold and affected ventilation and cerebral glucose and lactate metabolism ( P < 0.05), 3 days of high-dose EPO administration had no effect on cognition, voluntary activation, or exercise capacity, but ratings of perceived exertion increased ( P < 0.05). We confirmed that 3 mo of administration of EPO increases exercise capacity, but the improvement could not be accounted for by other mechanisms than enhanced oxygen delivery. In conclusion, EPO does not attenuate central fatigue or change cognitive performance strategy, suggesting that EPO enhances exercise capacity exclusively by increased oxygen delivery to the working muscles.

Perception of Effort during Constant Work to Self-Imposed Exhaustion

1979 ◽  
Vol 48 (3_suppl) ◽  
pp. 1111-1126 ◽  
Author(s):  
Donald H. Horstman ◽  
William P. Morgan ◽  
Allen Cymerman ◽  
James Stokes
Keyword(s):  
Perceived Exertion ◽  
Time To Exhaustion ◽  
Work Intensity ◽  
Ratings Of Perceived Exertion ◽  
Work Time ◽  
A Value ◽  
Perception Of Effort ◽  
Ventilatory Parameters ◽  
Effort Sense ◽  
High Work

The purpose of this study was to describe the pattern of change in effort sense and the value of this pattern in predicting work end-point at relatively high work intensity (80% V̇O2 max). The patterns of change of various physiological functions were also observed. Two modes of work (walking and running) were compared to ascertain generalizability of results. 26 healthy male volunteers served as subjects. Time to exhaustion (ET) did not differ between walking and running. As work continued during both tasks, significant increases of V̇E, V̇E/V̇O2, V̇E/V̇CO2 and HR and a significant decrease of ET were observed; while V̇O2 and R remained fairly constant. V̇O2 and V̇E during the run were about 5% greater than during the walk; there were no differences in other measures. Ratings of perceived exertion (RPE) from the Borg Scale were identical for both conditions, increasing in a near linear fashion from a value of 12.9 at 25% of total work time to 18.9 at exhaustion. Ratings obtained at 25 and 50% ET were extrapolated to time of exhaustion; the point of intercept corresponded to ratings of perceived exertion for maximal work. At exhaustion, subjects rated perception of respiratory exertion for the walk as less than that for the run; perception of leg exertion was not different for the two conditions. Plasma lactate, epinephrine and norepinephrine concentrations following exercise did not differ between the two conditions. The findings for the walking experiment were essentially replicated in a second investigation involving another 28 subjects. It is concluded that, with the exception of V̇O2 and some ventilatory parameters, walking and running ar the same relative work intensity resulted in comparable perceptual and physiological responses. Psychophysical judgments made early during work were reasonably accurate predictors of exhaustion time.

scholarly journals Caffeine effects on velocity selection and physiological responses during RPE production

2016 ◽  
Vol 41 (10) ◽  
pp. 1077-1082 ◽  
Author(s):  
James M. Green ◽  
Alyssa Olenick ◽  
Caroline Eastep ◽  
Lee Winchester
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Statistical Significance ◽  
Maximal Oxygen Consumption ◽  
Ratings Of Perceived Exertion ◽  
Caffeine Ingestion ◽  
Recreational Runners ◽  
Velocity Selection

Caffeine (CAF) blunts estimated ratings of perceived exertion (RPE) but the effects on RPE production are unclear. This study examined effects of acute caffeine ingestion during treadmill exercise where participants exercised at prescribed RPE 4 and 7. Recreational runners (maximal oxygen consumption = 51.4 ± 9.8 mL·kg−1·min−1) (n = 16) completed a maximal treadmill test followed by trials where they selected treadmill velocity (VEL) (1% grade) to produce RPE 4 and RPE 7 (10 min each). RPE production trials followed CAF (6 mg·kg−1) or placebo (PLA) (counterbalanced) ingestion. Participants were blinded to treadmill VEL but the Omni RPE scale was in full view. Repeated-measures ANOVA showed a main effect (trial) for VEL (CAF ∼5 m·min−1 faster) for RPE 4 (p = 0.07) and RPE 7 (p = 0.03). Mean heart rate and oxygen consumption responses were consistently higher for CAF but failed to reach statistical significance. Individual responses to CAF were labeled positive using a criterion of 13.4 m·min−1 faster for CAF (vs. PLA). Ten of 32 trials (31%) were positive responses. In these, systematic increases were observed for heart rate (∼12 beats·min−1) and oxygen consumption (∼5.7 mL·kg−1·min−1). Blunted/stable respiratory exchange ratio values at higher VEL for positive responders suggest increased free fatty acid reliance during CAF. In conlusion, mean results show a mild effect of CAF during RPE production. However, individual responses more clearly indicate whether a true effect is possible. Trainers and individuals should consider individual responses to ensure effectively intensity regulation.

scholarly journals Influence of Low Intensity Exercise in a Head Down Position-Using Oxygen Consumption(O2) and the Rate of Perceived Exertion (RPE)-

2005 ◽  
Vol 20 (3) ◽  
pp. 191-195
Author(s):  
Keita SHIMURA ◽  
Hiroyuki KOUNO ◽  
Kouhei KOKUBO ◽  
Yusuke NISHIDA ◽  
Hitoshi MARUYAMA
Keyword(s):  
Oxygen Consumption ◽  
Perceived Exertion ◽  
Low Intensity ◽  
Rate Of Perceived Exertion ◽  
Low Intensity Exercise

scholarly journals Potential Effect of Beetroot Juice Supplementation on Exercise Economy in Well-Trained Females

2021 ◽  
Author(s):  
Stacey P A Forbes ◽  
Lawrence L. Spriet
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Perceived Exertion ◽  
Potential Effect ◽  
Beetroot Juice ◽  
Ratings Of Perceived Exertion ◽  
Exercise Economy ◽  
Higher Power ◽  
Nitrate Supplementation ◽  
Power Outputs

This study examined if acute dietary nitrate supplementation (140 ml beetroot juice, BRJ) would reduce oxygen consumption (V̇O2) during cycling at power outputs of 50 and 70% V̇O2max in 14 well-trained female Canadian University Ringette League athletes. BRJ had no effect on VO2 or heart rate but significantly reduced ratings of perceived exertion (RPE) at both intensities. Individually, 4 participants responded to BRJ supplementation with a ≥3% reduction in V̇O2 at the higher power output. • Acute BRJ supplementation did not improve exercise economy in well-trained females, but significantly reduced RPE. However, 4/14 subjects did respond with a ≥3% V̇O2 reduction.

Comparison of Physiological Parameters During On-Water and Ergometer Kayaking and Their Relationship to Performance in Sprint Kayak Competitions

2020 ◽  
pp. 1-7
Author(s):  
Manuel Matzka ◽  
Christoph Zinner ◽  
Philipp Kunz ◽  
Hans-Christer Holmberg ◽  
Billy Sperlich
Keyword(s):  
Oxygen Consumption ◽  
Power Output ◽  
Perceived Exertion ◽  
Biceps Brachii ◽  
Saturation Index ◽  
Ratings Of Perceived Exertion ◽  
Physiological Indicators ◽  
Racing Performance ◽  
Ergometer Test ◽  
Incremental Testing

Purpose: (1) To compare various physiological indicators of performance during a 5 × 1500-m incremental kayak test performed on an ergometer and on-water and (2) to analyze the relationships between these indicators and the actual competition performance of elite sprint kayakers, aiming to provide information to coaches for evaluating and planning training on-water. Methods: A total of 14 male and female German elite sprint kayakers performed an incremental test both on an ergometer and on-water. The tissue saturation index of the musculus (m.) biceps brachii, oxygen consumption, ratings of perceived exertion, and levels of blood lactate were measured and compared with actual racing times. In addition, power output was monitored during ergometer testing only. Results: Oxygen consumption during the fourth (P = .02; d = 0.32) and final (fifth; P < .001; d = 0.32) steps of incremental testing was higher on-water than on the ergometer. The tissue saturation index of the m. biceps brachii was approximately 21% higher at the end of the ergometer test (P = .002; d = 1.14). During the second (P = .01; d = 0.78), third (P = .005; d = 0.93), and fourth stages (P = .005; d = 1.02), the ratings of perceived exertion for ergometer kayaking was higher. During the final step, power output was most closely correlated to 200- (r = .88), 500- (r = .93), and 1000-m (r = .86) racing times (all Ps < .01). Conclusions: During high-intensity kayaking on an ergometer or on-water, the oxygen consumption and tissue saturation index of the m. biceps brachii differ. Furthermore, at moderate to submaximal intensities, the ratings of perceived exertion were higher for ergometer than for on-water kayaking. Finally, of all parameters assessed, the power output during ergometer kayaking exhibited the strongest correlation with actual racing performance.

Wheelchair propulsion: effects of experience and push strategy on efficiency and perceived exertion

2008 ◽  
Vol 33 (5) ◽  
pp. 870-879 ◽  
Author(s):  
John P. Lenton ◽  
Neil E. Fowler ◽  
Lucas van der Woude ◽  
Victoria L. Goosey-Tolfrey
Keyword(s):  
Oxygen Consumption ◽  
Perceived Exertion ◽  
Maximal Exercise ◽  
Metabolic Cost ◽  
Peak Oxygen Consumption ◽  
Wheelchair Propulsion ◽  
Physiological Measures ◽  
Frequency Data ◽  
Ratings Of Perceived Exertion

The purpose of this study was to examine the role of wheeling experience on efficiency, metabolic cost, and differentiated ratings of perceived exertion (RPEs) during synchronous and asynchronous hand-rim propulsion with varying arm frequencies. Fourteen able-bodied (AB) male participants and 8 male wheelchair sportsmen (WS) performed tests of peak oxygen consumption for both propulsion modes. Subsequently, 2 series of five 4-min sub-maximal exercise bouts were completed at an individualized velocity (60% of peak oxygen consumption). Arm frequencies consisted of the freely chosen frequency (FCF), followed by 4 counter-balanced paced trials pushing at 60%, 80%, 120%, and 140% of the FCF. Efficiency indices (gross, GE; work, WE) were determined and peripheral (RPE-P), central (RPE-C), and overall (RPE-O) RPEs were recorded. The GE (6.4% vs. 8.4%) and WE (11.3% vs. 15.1%) were significantly higher in WS than in AB (p = 0.001). Trends in the oxygen consumption, GE, and WE data were similar in both groups, propulsion mode, and arm frequency. Data suggest that 80% FCF resulted in improved efficiency for both propulsion mode and group, although the differences between those arm frequencies immediately above and below were non-significant. Lower RPE scores corresponded with higher efficiency values. Regardless of group there were significant differences (p = 0.001) between the differentiated RPE measures, whereby RPE-P was on average always the highest score (13.1) and RPE-C the lowest (11.1; RPE-O was 12.2). In conclusion, despite the anticipated differences in efficiency between the WS and AB participants, this study confirmed that psycho-physiological measures produce similar trends to physiological measures with manipulations of both arm frequency and propulsion mode.

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