Intensity-dependent thermoregulatory responses at the onset of dynamic exercise in mildly heated humans

2003 ◽  
Vol 285 (1) ◽  
pp. R200-R207 ◽  
Author(s):  
Shuji Yanagimoto ◽  
Tomoko Kuwahara ◽  
Yuan Zhang ◽  
Shunsaku Koga ◽  
Yoshimitsu Inoue ◽  
...  
Keyword(s):  
Blood Flow ◽  
Exercise Intensity ◽  
Perceived Exertion ◽  
Dynamic Exercise ◽  
Rating Of Perceived Exertion ◽  
Cutaneous Blood Flow ◽  
Cycle Exercise ◽  
Arterial Blood ◽  
The Mean ◽  
Cutaneous Blood

To investigate quantitatively how sweating and cutaneous blood flow responses at the onset of dynamic exercise are affected by increasing exercise intensity in mildly heated humans, 18 healthy male subjects performed cycle exercise at 30, 50, and 70% of maximal O2 uptake (V̇O2 max) for 60 s in a warm environment. The study was conducted in a climatic chamber with a regulated ambient temperature of 35°C and relative humidity of 50%. The subjects rested in the semisupine position in the chamber for 60 min, and then sweating rate (SR) and skin blood flow were measured during cycle exercise at three different intensities. Changes in the heart rate, rating of perceived exertion, and mean arterial blood pressure were proportional to increasing exercise intensity, whereas esophageal and mean skin temperatures were essentially constant throughout the experiment. The SR on the chest, forearm, and thigh, but not on the palm, increased significantly with increasing exercise intensity ( P < 0.05). The mean SR of the chest, forearm, and thigh increased 0.05 mg·cm-2·min-1 with an increase in exercise intensity equivalent to 10% V̇O2 max. On the other hand, the cutaneous vascular conductance (CVC) on the chest, forearm, and palm decreased significantly with increasing exercise intensity ( P < 0.05). The mean CVC of the chest and forearm decreased 5.5% and the CVC on the palm decreased 8.0% with an increase in exercise intensity equivalent to 10% V̇O2 max. In addition, the reduction in CVC was greater on the palm than on the chest and forearm at all exercise intensities ( P < 0.01). We conclude that nonthermal sweating and cutaneous blood flow responses are exercise intensity dependent but directionally opposite at the onset of dynamic exercise in mildly heated humans. Furthermore, cutaneous blood flow responses to increased exercise intensity are greater in glabrous (palm) than in nonglabrous (chest and forearm) skin.

Local sweating and cutaneous blood flow during exercise in hypobaric environments

1987 ◽  
Vol 62 (6) ◽  
pp. 2224-2229 ◽  
Author(s):  
M. A. Kolka ◽  
L. A. Stephenson ◽  
P. B. Rock ◽  
R. R. Gonzalez
Keyword(s):  
Blood Flow ◽  
Hypobaric Hypoxia ◽  
Aerobic Power ◽  
Venous Occlusion ◽  
Dew Point ◽  
Cutaneous Blood Flow ◽  
Acute Hypobaric Hypoxia ◽  
The Mean ◽  
Body Cooling ◽  
Cutaneous Blood

The effect of acute hypobaric hypoxia on local sweating and cutaneous blood flow was studied in four men and four women (follicular phase of menstrual cycle), who exercised at 60% of their altitude-specific peak aerobic power for 35 min at barometric pressures (PB) of 770 Torr (sea level), 552 Torr (2,596 m), and 428 Torr (4,575 m) at an ambient temperature of 30 degrees C. We measured esophageal temperature (Tes), mean skin temperature (Tsk, 8 sites), and local sweating (ms) from dew-point sensors attached to the skin at the chest, arm, and thigh. Skin blood flow (SkBF) of the forearm was measured once each minute by venous occlusion plethysmography. There were no gender differences in the sensitivity (slope) or the threshold of either ms/Tes or SkBF/Tes at any altitude. No change in the Tes for sweating onset occurred with altitude. The mean slopes of the ms/Tes relationships for the three regional sites decreased with increasing altitude, although these differences were not significant between the two lower PBS. The slope of SkBF/Tes was reduced in five of the eight subjects at 428 Torr. Enhanced body cooling as a response to the higher evaporative capacity of the environment is suggested as a component of these peripheral changes occurring in hypobaric hypoxia.

Neural control of the forearm cutaneous vasoconstrictor response to dynamic exercise

1991 ◽  
Vol 71 (5) ◽  
pp. 1892-1896 ◽  
Author(s):  
D. B. Friedman ◽  
J. M. Johnson ◽  
J. H. Mitchell ◽  
N. H. Secher
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Perceived Exertion ◽  
Dynamic Exercise ◽  
Rating Of Perceived Exertion ◽  
Doppler Flowmetry ◽  
Low Intensity ◽  
Vasoconstrictor Response ◽  
Low Intensity Exercise ◽  
Exercise In Humans

This study was designed to evaluate the relative importance of intended effort (“central command”) and of the absolute intensity of dynamic exercise to the cutaneous vasoconstrictor response to the onset of exercise in humans. Skin blood flow (laser-Doppler flowmetry) was measured from the forearm in six healthy individuals during 3-min periods of high- and low-intensity exercise with and without partial neuromuscular blockade. Cutaneous vascular conductance (CVC) was calculated from the ratio of skin blood flow to mean arterial pressure and expressed as a percent change from rest. A rating of perceived exertion (RPE) was expressed as a subjective measure of intended effort. Under control conditions, CVC decreased by 22% (median; range 7–42%, P less than 0.05) during high-intensity exercise [218 (186–268) W; RPE 16 (14–19) exertion units]. In contrast, during control low-intensity exercise [106 (88–128) W; RPE 10 (9–14) exertion units], during low-level exercise with curare [77 (54–98) W; RPE 13 (11–16) exertion units], and during maximal exercise with curare [106 (88–124) W; RPE 19 (18–20) exertion units], CVC did not change significantly. These results suggest that factors related to the activity of the exercising muscle and its metabolism rather than intended effort determine the cutaneous vasoconstrictor response to the initiation of intense dynamic exercise in humans.

scholarly journals Use of the CR100 Scale for Session Rating of Perceived Exertion in Soccer and Its Interchangeability With the CR10

2016 ◽  
Vol 11 (3) ◽  
pp. 388-392 ◽  
Author(s):  
Maurizio Fanchini ◽  
Ivan Ferraresi ◽  
Roberto Modena ◽  
Federico Schena ◽  
Aaron J. Coutts ◽  
...  
Keyword(s):  
Heart Rate ◽  
Construct Validity ◽  
Body Mass ◽  
Exercise Intensity ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Soccer Players ◽  
Bland Altman Method ◽  
Rate Method ◽  
The Mean

Purpose:To examine the construct validity of the session rating perceived exertion (s-RPE) assessed with the Borg CR100 scale to measure training loads in elite soccer and to examine if the CR100 is interchangeable and can provide more-accurate ratings than the CR10 scale.Methods:Two studies were conducted. The validity of the CR100 was determined in 19 elite soccer players (age 28 ± 6 y, height 180 ± 7 cm, body mass 77 ± 6 kg) during training sessions through correlations with the Edwards heart-rate method (study 1). The interchangeability with CR10 was assessed in 78 soccer players (age 19.3 ± 4.1 y, height 178 ± 5.9 cm, body mass 71.4 ± 6.1 kg) through the Bland–Altman method and correlations between change scores in different sessions. To examine whether the CR100 is more finely graded than the CR10, the proportions of responses corresponding to the verbal expressions were calculated (study 2).Results:Individual correlations between the Edwards method and s-RPE were large to very large (.52–.85). The mean difference between the 2 scales was –0.3 ± 0.33 AU (90% CI –0.41 to –0.29) with 95% limits of agreements (0.31 to –0.96 AU). Correlations between scales and between-changes scores were nearly perfect (.95 and .91–.98). Ratings corresponding to the verbal anchors were 49% in CR10 and 26% in CR100.Conclusions:The CR100 is valid for assessing the training load in elite soccer players. It can be used interchangeably with the CR10 and may provide more-precise measures of exercise intensity.

Endothelin-1-mediated vasoconstriction at rest and during dynamic exercise in healthy humans

2007 ◽  
Vol 293 (4) ◽  
pp. H2550-H2556 ◽  
Author(s):  
D. Walter Wray ◽  
Steven K. Nishiyama ◽  
Anthony J. Donato ◽  
Mikael Sander ◽  
Peter D. Wagner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Exercise Intensity ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Dynamic Exercise ◽  
Dependent Manner ◽  
Drug Infusion ◽  
Leg Blood Flow ◽  
Healthy Humans ◽  
Arterial Blood

It is now generally accepted that α-adrenoreceptor-mediated vasoconstriction is attenuated during exercise, but the efficacy of nonadrenergic vasoconstrictor pathways during exercise remains unclear. Thus, in eight young (23 ± 1 yr), healthy volunteers, we contrasted changes in leg blood flow (ultrasound Doppler) before and during intra-arterial infusion of the α1-adrenoreceptor agonist phenylephrine (PE) with that of the nonadrenergic endothelin A (ETA)/ETB receptor agonist ET-1. Heart rate, arterial blood pressure, common femoral artery diameter, and mean blood velocity were measured at rest and during knee-extensor exercise at 20%, 40%, and 60% of maximal work rate (WRmax). Drug infusion rates were adjusted for blood flow to maintain comparable doses across all subjects and conditions. At rest, PE infusion (8 ng·ml−1·min−1) provoked a rapid and significant decrease in leg blood flow (−51 ± 3%) within 2.5 min. Resting ET-1 infusion (40 pg·ml−1·min−1) significantly decreased leg blood flow within 5 min, reaching a maximal vasoconstriction (−34 ± 3%) after 25–30 min of continuous infusion. Compared with rest, an exercise intensity-dependent attenuation to PE-mediated vasoconstriction was observed (−18 ± 5%, −7 ± 2%, and −1 ± 3% change in leg blood flow at 20%, 40%, and 60% of WRmax, respectively). Vasoconstriction in response to ET-1 was also blunted in an exercise intensity-dependent manner (−13 ± 3%, −7 ± 4%, and 2 ± 3% change in leg blood flow at 20%, 40%, and 60% of WRmax, respectively). These findings support a significant contribution of ET-1 and α-adrenergic receptors in the regulation of skeletal muscle blood flow in the human leg at rest and suggest a similar, intensity-dependent “lysis” of peripheral ET and α-adrenergic vasoconstriction during dynamic exercise.

The Vasostimulant Effect of the Electric Pulse Stimulator on the Cutaneous Blood Flow.

1997 ◽  
Vol 59 (2) ◽  
pp. 255-256
Author(s):  
Yuka NAKAMURA ◽  
Shinichi WATANABE ◽  
Hisashi TAKAHASHI ◽  
Atsuhiko HASEGAWA
Keyword(s):  
Blood Flow ◽  
Electric Pulse ◽  
Cutaneous Blood Flow ◽  
Cutaneous Blood

Physiological Demands of Basic Fire Management Tasks in Members of the Canadian Armed Forces: A Pilot Study

2021 ◽  
Author(s):  
Étienne Chassé ◽  
Daniel Théoret ◽  
Martin P Poirier ◽  
François Lalonde
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Fire Management ◽  
Armed Forces ◽  
Rating Of Perceived Exertion ◽  
Minimum Standard ◽  
Canadian Armed Forces ◽  
The Mean ◽  
Physiological Demands ◽  
Task Simulation

ABSTRACT Introduction Members of the Canadian Armed Forces (CAF) are required to meet the minimum standards of the Fitness for Operational Requirements of CAF Employment (FORCE) job-based simulation test (JBST) and must possess the capacity to perform other common essential tasks. One of those tasks is to perform basic fire management tasks during fire emergencies to mitigate damage and reduce the risk of injuries and/or death until professional firefighters arrive at the scene. To date however, the physiological demands of common firefighting tasks have mostly been performed on professional firefighters, thus rendering the transferability of the demands to the general military population unclear. This pilot study aimed to quantify, for the first time, the physiological demands of basic fire management tasks in the military, to determine if they are reflected in the FORCE JBST minimum standard. We hypothesized that the physiological demands of basic fire management tasks within the CAF are below the physiological demands of the FORCE JBST minimum standard, and as such, be lower than the demands of professional firefighting. Materials and methods To achieve this, 21 CAF members (8 females; 13 males; mean [SD] age: 33 [10] years; height: 174.5 [10.5] cm; weight: 85.4 [22.1] kg, estimated maximal oxygen uptake [$\dot V$O2peak]: 44.4 (7.4) mL kg−1 min−1) participated in a realistic, but physically demanding, JBST developed by CAF professional firefighting subject matter experts. The actions included lifting, carrying, and manipulating a 13-kg powder fire extinguisher and connecting, coupling, and dragging a 38-mm fire hose over 30 m. The rate of oxygen uptake ($\dot V$O2), heart rate, and percentage of heart rate reserve were measured continuously during two task simulation trials, which were interspersed by a recovery period. Rating of perceived exertion (6-no exertion; 20-maximal exertion) was measured upon completion of both task simulations. Peak $\dot V$O2 ($\dot V$O2peak) was estimated based on the results of the FORCE JBST. Results The mean (SD) duration of both task simulation trials was 3:39 (0:19) min:s, whereas the rest period in between both trials was 62 (19) minutes. The mean O2 was 21.1 (4.7) mL kg−1 min−1 across trials, which represented 52.1 (12.2) %$\dot V$O2peak and ∼81% of the FORCE JBST. This was paralleled by a mean heart rate of 136 (18) beats min−1, mean percentage of heart rate reserve of 61.2 (10.8), and mean rating of perceived exertion of 11 ± 2. Other physical components of the JBST consisted of lifting, carrying, and manipulating a 13-kg load for ∼59 seconds, which represents 65% of the load of the FORCE JBST. The external resistance of the fire hose drag portion increased up to 316 N, translating to a total of 6205 N over 30 m, which represents 96% of the drag force measured during the FORCE JBST. Conclusions Our findings demonstrate that the physiological demands of basic fire management tasks in the CAF are of moderate intensity, which are reflected in the CAF physical fitness standard. As such, CAF members who achieve the minimum standard on the FORCE JBST are deemed capable of physically performing basic fire management tasks during fire emergencies.

Carbohydrate Drink Use During 30 Minutes of Variable-Intensity Exercise Has No Effect on Exercise Performance in Premenarchal Girls

2021 ◽  
Vol 33 (2) ◽  
pp. 65-69
Author(s):  
C. Eric Heidorn ◽  
Brandon J. Dykstra ◽  
Cori A. Conner ◽  
Anthony D. Mahon
Keyword(s):  
Peak Power ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Fatigue Index ◽  
Mean Power ◽  
Variable Intensity ◽  
Performance Effects ◽  
Power Peak ◽  
The Mean ◽  
And Performance

Purpose: This study examined the physiological, perceptual, and performance effects of a 6% carbohydrate (CHO) drink during variable-intensity exercise (VIE) and a postexercise test in premenarchal girls. Methods: A total of 10 girls (10.4 [0.7] y) participated in the study. VO2peak was assessed, and the girls were familiarized with VIE and performance during the first visit. The trial order (CHO and placebo) was randomly assigned for subsequent visits. The drinks were given before VIE bouts and 1-minute performance (9 mL/kg total). Two 15-minute bouts of VIE were completed (10 repeated sequences of 20%, 55%, and 95% power at VO2peak and maximal sprints) before a 1-minute performance sprint. Results: The mean power, peak power, heart rate (HR), %HRpeak, and rating of perceived exertion during VIE did not differ between trials. However, the peak power decreased, and the rating of perceived exertion increased from the first to the second bout. During the 1-minute performance, there were no differences between the trial (CHO vs placebo) for HR (190 [9] vs 189 [9] bpm), %HRpeak (97.0% [3.2%] vs 96.6% [3.0%]), rating of perceived exertion (7.8 [2.3] vs 8.1 [1.9]), peak power (238 [70] vs 235 [60] W), fatigue index (54.7% [10.0%] vs 55.9% [12.8%]), or total work (9.4 [2.6] vs 9.4 [2.1] kJ). Conclusion: CHO supplementation did not alter physiological, perceptual, or performance responses during 30 minutes of VIE or postexercise sprint performance in premenarchal girls.

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.

Relation of local skin temperature and local sweating to cutaneous blood flow

1963 ◽  
Vol 18 (4) ◽  
pp. 781-785 ◽  
Author(s):  
Leo C. Senay ◽  
Leon D. Prokop ◽  
Leslie Cronau ◽  
Alrick B. Hertzman
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Sweat Gland ◽  
Cutaneous Blood Flow ◽  
Local Skin ◽  
Cutaneous Vasodilatation ◽  
Local Skin Temperature ◽  
Relationship Of ◽  
The Relationship ◽  
Cutaneous Blood

The relationship of local skin temperature and the onset of sweating to the local cutaneous blood flow was studied in the forearm and calf. The purpose of the investigation was to appraise the possible relation of sweat gland activity to the cutaneous vasodilatation which has been attributed to bradykinin or to intracranial temperatures. The onset of sweating was not marked by any apparently related increases in the rate of cutaneous blood flow. On the contrary, the onset of sweating was followed often by a stabilization or even a decrease in the level of cutaneous blood flow. The relations of the latter to the local skin temperature were complex, particularly in the forearm. There appeared to be additional unidentified influences, possibly vasomotor, operating on the skin vessels during transitional phases in the relation of skin temperature to blood flow. Submitted on October 15, 1962

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