scholarly journals Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242916
Author(s):  
Hidenori Otani ◽  
Takayuki Goto ◽  
Yuki Kobayashi ◽  
Minayuki Shirato ◽  
Heita Goto ◽  
...  
Keyword(s):  
Heat Stress ◽  
Air Conditioning ◽  
Perceived Exertion ◽  
Thermal Sensation ◽  
Progressive Increase ◽  
Time Of Day ◽  
Rating Of Perceived Exertion ◽  
Tympanic Temperature ◽  
Late Afternoon ◽  
Indoor And Outdoor

Purpose The time-of-day variations in environmental heat stress have been known to affect thermoregulatory responses and the risk of exertional heat-related illness during outdoor exercise in the heat. However, such effect and risk are still needed to be examined during indoor sports/exercises. The current study investigated the diurnal relationships between thermoregulatory strain and environmental heat stress during regular judo training in a judo training facility without air conditioning on a clear day in the heat of summer. Methods Eight male high school judokas completed two 2.5-h indoor judo training sessions. The sessions were commenced at 09:00 h (AM) and 16:00 h (PM) on separate days. Results During the sessions, indoor and outdoor heat stress progressively increased in AM but decreased in PM, and indoor heat stress was less in AM than PM (mean ambient temperature: AM 32.7±0.4°C; PM 34.4±1.0°C, P<0.01). Mean skin temperature was higher in AM than PM (P<0.05), despite greater dry and evaporative heat losses in AM than PM (P<0.001). Infrared tympanic temperature, heart rate and thermal sensation demonstrated a trial by time interaction (P<0.001) with no differences at any time point between trials, showing relatively higher responses in these variables in PM compared to AM during the early stages of training and in AM compared to PM during the later stages of training. There were no differences between trials in body mass loss and rating of perceived exertion. Conclusions This study indicates a greater thermoregulatory strain in the morning from 09:00 h than the late afternoon from 16:00 h during 2.5-h regular judo training in no air conditioning facility on a clear day in the heat of summer. This observation is associated with a progressive increase in indoor and outdoor heat stress in the morning, despite a less indoor heat stress in the morning than the afternoon.

scholarly journals Heat Acclimation by Postexercise Hot-Water Immersion: Reduction of Thermal Strain During Morning and Afternoon Exercise-Heat Stress After Morning Hot-Water Immersion

2018 ◽  
Vol 13 (10) ◽  
pp. 1281-1286 ◽  
Author(s):  
Michael J. Zurawlew ◽  
Jessica A. Mee ◽  
Neil P. Walsh
Keyword(s):  
Heat Stress ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Perceived Exertion ◽  
Water Immersion ◽  
Heat Acclimation ◽  
Time Of Day ◽  
Hot Water ◽  
Rating Of Perceived Exertion ◽  
Hot Water Immersion

Purpose: Recommendations state that to acquire the greatest benefit from heat-acclimation, the clock time of heat-acclimation sessions should match that of expected exercise-heat stress. It remains unknown if adaptations by postexercise hot-water immersion (HWI) demonstrate time-of-day-dependent adaptations. Thus, the authors examined whether adaptations following postexercise HWI completed in the morning were present during morning and afternoon exercise-heat stress. Methods: Ten males completed an exercise-heat stress test commencing in the morning (9:45 AM) and afternoon (2:45 PM; 40 min; 65% of maximal oxygen uptake treadmill run) before and after heat-acclimation. The 6-d heat-acclimation intervention involved a daily 40-min treadmill run (65% of maximal oxygen uptake) in temperate conditions followed by ≤40-min HWI (40°C; 6:30–11:00 AM). Results: Adaptations by 6-d postexercise HWI in the morning were similar in the morning and afternoon. Reductions in resting rectal temperature (Tre) (AM −0.34°C [0.24°C], PM −0.27°C [0.23°C]; P = .002), Tre at sweating onset (AM −0.34°C [0.24°C], PM −0.31°C [0.25°C]; P = .001), and end-exercise Tre (AM −0.47°C [0.33°C], PM −0.43°C [0.29°C]; P = .001), heart rate (AM −14 [7] beats·min−1, PM −13 [6] beats·min−1; P < .01), rating of perceived exertion (P = .01), and thermal sensation (P = .005) were not different in the morning compared with the afternoon. Conclusion: Morning heat acclimation by postexercise HWI induced adaptations at rest and during exercise-heat stress in the morning and midafternoon.

scholarly journals Changes in Markers of Oxidative Stress and α-Amylase in Saliva of Children Associated with a Tennis Competition

2020 ◽  
Vol 17 (17) ◽  
pp. 6269 ◽  
Author(s):  
José María Giménez-Egido ◽  
Raquel Hernández-García ◽  
Damián Escribano ◽  
Silvia Martínez-Subiela ◽  
Gema Torres-Luque ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Capacity ◽  
Psychological Stress ◽  
Antioxidant Status ◽  
Perceived Exertion ◽  
Progressive Increase ◽  
Rating Of Perceived Exertion ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Reducing Ability ◽  
Trolox Equivalent

The purpose of this paper was to analyze the changes caused by a one-day tennis tournament in biomarkers of oxidative stress and α-amylase in saliva in children. The sample was 20 male active children with the following characteristics: (a) age of players = 9.46 ± 0.66 years; (b) weight = 34.8 ± 6.5 kg; (c) height = 136.0 ± 7.9 cm; (d) mean weekly training tennis = 2.9 ± 1.0 h. The tennis competition ran for one day, with four matches for each player. Data were taken from the average duration per match and the rating of perceived exertion (RPE). Four biomarkers of antioxidant status: uric acid (AU), Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of saliva (FRAS, cupric reducing antioxidant capacity (CUPRAC) and salivary alpha-amylase (sAA) as a biomarker of psychological stress were measured in saliva. The time points were baseline (at home before the tournament), pre-competition (immediately before the first match) and post-match (after each match) measurements. The four biomarkers of antioxidant status showed a similar dynamic with lower values at baseline and a progressive increase during the four matches. Overall one-day tennis competition in children showed a tendency to increase antioxidant biomarkers in saliva. In addition, there was an increase in pre-competition sAA possibly associated with psychological stress. Further studies about the possible physiological implications of these findings should be performed in the future.

scholarly journals Practical Torso Cooling During Soccer-Specific Exercise in the Heat

2018 ◽  
Vol 53 (11) ◽  
pp. 1089-1097 ◽  
Author(s):  
Kirstie Parris ◽  
Christopher J. Tyler
Keyword(s):  
Perceived Exertion ◽  
Intermittent Exercise ◽  
Thermal Sensation ◽  
Sprint Performance ◽  
Rating Of Perceived Exertion ◽  
Sprint Speed ◽  
Minute Period ◽  
Improve Exercise Performance ◽  
C 50 ◽  
Cool Conditions

Context Precooling and midevent cooling of the torso using cooling vests can improve exercise performance in the heat with or without physiological changes; however, the effects of such cooling during intermittent exercise in the heat are unknown. Objective To investigate the effects of torso cooling during intermittent exercise in the heat (35°C, 50% relative humdity) on sprint performance and the physiological and perceptual responses to the exercise. Design Crossover study. Setting Walk-in environmental chamber. Patients or Other Participants Ten non–heat-acclimated, male soccer players (age = 25 ± 2 years, height = 1.77 ± 0.06 m, mass = 72.9 ± 7.6 kg). Intervention(s) Two 90-minute bouts of soccer-specific intermittent running in the heat: 1 trial with a cooling vest worn during the exercise and 1 trial without a cooling vest. Each trial comprised two 45-minute periods separated by approximately 15 minutes of seated rest in cool conditions (approximately 23°C, 50% relative humdity). Main Outcome Measure(s) Peak sprint speed, rectal temperature (Tr), mean-weighted skin temperature (Tsk), heart rate (HR), rating of perceived exertion (RPE), and thermal sensation (TS) were measured every 5 minutes. Results Peak sprint performance was largely unaffected by the cooling vest. The Tr, Tsk, HR, RPE, and TS were unaffected in the cooling-vest trial during the first 45 minutes, but Tr rose at a slower rate in the cooling-vest trial (0.026°C.min–1 ± 0.008°C.min–1) than in the no-vest trial (0.032°C.min–1 ± 0.009°C.min–1). During the second 45-minute period, Tr, Tr rate of rise, Tsk, RPE, and TS were lower in the cooling-vest trial (Hedges g range, 0.55–0.84), but mean HR was unaffected. Conclusions Wearing a cooling vest during soccer-specific intermittent running in the heat reduced physiological and perceptual strain but did not increase peak sprint speed.

scholarly journals Effects of Half-Time Cooling Using a Fan with Skin Wetting on Thermal Response During Intermittent Cycling Exercise in the Heat

2021 ◽  
Vol 05 (03) ◽  
pp. E91-E98
Author(s):  
Jumpei Osakabe ◽  
Masanobu Kajiki ◽  
Kiho Kondo ◽  
Takaaki Matsumoto ◽  
Yoshihisa Umemura
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Rating Of Perceived Exertion ◽  
Half Time ◽  
Physiological Strain ◽  
Cycling Exercise ◽  
Repeated Sprint ◽  
Significant Difference ◽  
Sprint Cycling ◽  
Experimental Trials

AbstractThe present study investigated the effects of half-time (HT) break cooling using a fan and damp sponge on physiological and perceptual responses during the 2nd half of a repeated-sprint exercise in a hot environment. Eight physically active men performed a familiarization trial and two experimental trials of a 2×30-min intermittent cycling exercise protocol with a 15-min HT break in hot conditions (35°C, 50% relative humidity). Two experimental trials were conducted in random order: skin wetting with a fan (FANwet) and no cooling (CON). During the 2nd half, a repeated-sprint cycling exercise was performed: i. e., 5 s of maximal pedaling (body weight×0.075 kp) every minute, separated by 25 s of unloaded pedaling (80 rpm) and 30 s of rest. Rectal temperature, skin temperature (chest, forearm, thigh, and calf), heart rate, physiological strain index, rating of perceived exertion, thermal sensation, and comfort were significantly improved in the FANwet condition (P<0.05). There was no significant difference in the repeated-sprint cycling exercise performance between conditions. The results suggest that skin wetting with a fan during the HT break is a practical and effective cooling strategy for mitigating physiological and perceptual strain during the 2nd half in hot conditions.

scholarly journals The Impact of Wrist Percooling on Physiological and Perceptual Responses during a Running Time Trial Performance in the Heat

2020 ◽  
Vol 17 (20) ◽  
pp. 7559
Author(s):  
Kelsey Denby ◽  
Ronald Caruso ◽  
Emily Schlicht ◽  
Stephen J. Ives
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Thermal Sensation ◽  
Maximal Oxygen Consumption ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Running Speed ◽  
Running Time ◽  
The Impact ◽  
Trial Performance

Environmental heat stress poses significant physiological challenge and impairs exercise performance. We investigated the impact of wrist percooling on running performance and physiological and perceptual responses in the heat. In a counterbalanced design, 13 trained males (33 ± 9 years, 15 ± 7% body fat, and maximal oxygen consumption, VO2max 59 ± 5 mL/kg/min) completed three 10 km running time trials (27 °C, 60% relative humidity) while wearing two cooling bands: (1) both bands were off (off/off), (2) one band on (off/on), (3) both bands on (on/on). Heart rate (HR), HR variability (HRV), mean arterial pressure (MAP), core temperature (TCO), thermal sensation (TS), and fatigue (VAS) were recorded at baseline and recovery, while running speed (RS) and rating of perceived exertion (RPE) were collected during the 10 km. Wrist cooling had no effect (p > 0.05) at rest, except modestly increased HR (3–5 ∆beats/min, p < 0.05). Wrist percooling increased (p < 0.05) RS (0.25 ∆mi/h) and HR (5 ∆beats/min), but not TCO (∆ 0.3 °C), RPE, or TS. Given incomplete trials, the distance achieved at 16 min was not different between conditions (off/off 1.96 ± 0.16 vs. off/on 1.98 ± 0.19 vs. on/on 1.99 ± 0.24 miles, p = 0.490). During recovery HRV, MAP, or fatigue were unaffected (p > 0.05). We demonstrate that wrist percooling elicited a faster running speed, though this coincides with increased HR; although, interestingly, sensations of effort and thermal comfort were unaffected, despite the faster speed and higher HR.

scholarly journals Warm-up durations in a hot-dry climate affect thermoregulation, mean power-output and fatigue, but not peak power in specific soccer repeated-sprint ability

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohamed Frikha ◽  
Nesrine Chaâri ◽  
Noureddine Ben Said ◽  
Mohammed Shaab Alibrahim
Keyword(s):  
Power Output ◽  
Peak Power ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Tympanic Temperature ◽  
Muscular Power ◽  
Mean Power ◽  
Warm Up ◽  
Repeated Sprint ◽  
Mean Power Output

Abstract Background This study addressed the lack of data on the effect of warm-up (WU) duration in hot-dry climate (~ 30 °C; ~ 18% RH), on thermoregulation, muscular power-output, and fatigue after specific soccer repeated-sprint test (RSA). Methods Eleven amateur soccer players participated in a cross-over randomized study and they underwent the Bangsbo repeated-sprint test, after three WU durations (i.e. WU10, WU15 and WU20 min) at 70% of MAV, and on different days. Peak power (PP), mean power (MP) and the fatigue index (FI) were recorded and analyzed. Likewise, heart rate (HR), tympanic temperature (Ttym), mean body temperature (MBT) and rating of perceived exertion (RPE) were recorded during each session. Results The repeated measure ANOVA showed that MP improved after WU15 in comparison to WU10 and WU20 (p = 0.04 and p = 0.001; respectively). Nonetheless, no significant effect on PP was recorded after all WU durations. FI during RSA increased after WU20 in comparison to WU15 and WU10 (p < 0.001 and p = 0.003; respectively). Higher RPE values (p < 0.001) were recorded after WU15 and WU20 in comparison to WU10 duration. The two-way ANOVA showed higher ΔTtym and ΔMBT values after WU15 and WU20 compared to WU10 (p = 0.039 and p < 0.001for Ttym; p = 0.005 and p < 0.001 for MBT, respectively). Conclusions The WU15 at 70% of MAV better assists mean power-output during soccer RSA in hot-dry (~ 30 °C; 18% RH) climate, but not peak power. Reducing WU duration up to 10 min seems to be insufficient to induce beneficial physiological changes necessary for optimizing repeated-sprint performance, while its extension up to 20 min remains detrimental for muscular power and induces higher fatigue.

Heat Added to Repeated-Sprint Training in Hypoxia Does Not Affect Cycling Performance

2021 ◽  
pp. 1-9
Author(s):  
Myles C. Dennis ◽  
Paul S.R. Goods ◽  
Martyn J. Binnie ◽  
Olivier Girard ◽  
Karen E. Wallman ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Core Temperature ◽  
Perceived Exertion ◽  
Thermal Sensation ◽  
Rating Of Perceived Exertion ◽  
Sprint Training ◽  
Active Recovery ◽  
Repeated Sprint ◽  
Air Temperatures ◽  
Desirable Outcome

Purpose: This study aimed to assess the influence of graded air temperatures during repeated-sprint training in hypoxia (RSH) on performance and physiological responses. Methods: Ten well-trained athletes completed one familiarization and 4 experimental sessions at a simulated altitude of 3000 m (0.144 FIO2) above sea level. Air temperatures utilized across the 4 experimental sessions were 20°C, 25°C, 30°C, and 35°C (all 50% relative humidity). The participants performed 3 sets of 5 × 10 seconds “all-out” cycle sprints, with 20 seconds of active recovery between sprints and 5 minutes of active recovery between sets (recovery intensity = 120 W). Core temperature, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion, and thermal sensation were collected. Results: There were no differences between conditions for peak power, mean power, and total work in each set (P > .05). There were no condition × time interaction effects for any variables tested. The peak core temperature was highest at 30°C (38.06°C [0.31°C]). Overall, the pulse oxygen saturation was higher at 35°C than at 20°C (P < .001; d < 0.8), 25°C (P < .001; d = 1.12 ± 0.54, large), and 30°C (P < .001; d = 0.84 ± 0.53, large). Conclusion: Manipulating air temperature between 20°C and 35°C had no effect on performance or core temperature during a typical RSH session. However, the pulse oxygen saturation was preserved at 35°C, which may not be a desirable outcome for RSH interventions. The application of increased levels of ambient heat may require a different approach if augmenting the RSH stimulus is the desired outcome.

scholarly journals Thermoregulatory Responses After Uphill Running While Wearing Enforcement Personnel Clothing

2021 ◽  
Vol 18 (1) ◽  
pp. 143
Author(s):  
Norhayaty Zahari ◽  
Mohd Rozi Ahmad ◽  
Raja Mohammed Firhad Raja Azi ◽  
Ridwan Yahaya ◽  
Ahmad Munir Che Muhamed ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Material Composition ◽  
Rating Of Perceived Exertion ◽  
Thermoregulatory Response ◽  
Freedom Of Movement ◽  
Clothing Comfort ◽  
Thermoregulatory Responses ◽  
Clothing Type ◽  
Skin Wetness

The choice of clothing for enforcement personnel is vital to ensure minimum physical interference and optimum freedom of movement. The clothing type and fibre composition are important factors that have strong influence on the activities of enforcement personnel. This study presents an evaluation of the thermoregulatory responses for two type of enforcement personnel clothing after uphill running with different material composition.  Eight recreational trained respondents (age, 24.4 ± 2.3; height, 166.9 ± 3.3; body weight, 64.0 ± 5.8; BMI 23.0 ± 1.8) completed an 8 km run on a treadmill with 6% elevation wearing enforcement personnel clothing. Both clothing used in the trials were made of polyester/cotton (P50C50) and nylon/cotton (N20C80) material composition. The finding revealed that compared to P50C50 clothing, the N20C80 clothing does not have a good thermal balance. The loss of body mass did not vary significantly but the sweating rate differed significantly between trials (P = 0.008). The Rating of Perceived Exertion (RPE) of the participants was rated higher for N20C80 as compared to P50C50. The thermal sensation (P < 0.001), sweating sensation (P = 0.05), skin wetness (P = 0.007), clothing comfort (P < 0.01) and clothing humidity (P = 0.001) were significantly greater with N20C80 compared to P50C50 during exercise. The P50C50 clothing was more convenient to wear for the uphill running during the exercise. This study suggested that P50C50 would provide a better thermoregulatory response to regulate the thermal equilibrium between human skin and the environment.

scholarly journals The Effects of Exercise Difficulty and Time-of-Day on the Perception of the Task and Soccer Performance in Child Soccer Players

Children ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 793
Author(s):  
Liwa Masmoudi ◽  
Adnene Gharbi ◽  
Cyrine H’Mida ◽  
Khaled Trabelsi ◽  
Omar Boukhris ◽  
...  
Keyword(s):  
Task Difficulty ◽  
Perceived Exertion ◽  
Time Pressure ◽  
Absolute Error ◽  
Time Of Day ◽  
Rating Of Perceived Exertion ◽  
Long Distance ◽  
Perceived Difficulty ◽  
Ball Velocity ◽  
Speed Accuracy

In soccer, accurate kicking skills are important determinants of successful performance. A successful kick must meet several criteria, including speed, accuracy, and timing. In fact, players who are able to kick the ball more accurately under various difficulties, such as time pressure, space constraints, the opponent’s pressure, and the distance between the kicking point and the goal, have a clear advantage during soccer games. The aim of the present study was to investigate the effect of exercise difficulty and time-of-day on perceived task difficulty and kicking performance. Accordingly, 32 boys (age: 11 ± 0.7 years; height: 1.45 ± 0.07 m; body-mass: 38.9 ± 7.8 kg) performed shooting accuracy tests under two difficulty levels (distance (long-distance (LD) vs. short-distance (SD)) and time pressure (Without-time-pressure (WTP) vs. With-time-pressure (TP)) at 08:00 h and 17:00 h. Absolute-error, variable-error, and constant-error were evaluated during the kicking tasks, in addition to ball velocity and shooting quality. Moreover, rating-of-perceived-exertion score (RPE), feeling-scale (FS), and perceived difficulty were completed immediately at the end of each test. The results showed that shooting quality was not affected by the time-of-day, but it was better in WTP vs. TP (p < 0.05), and in SD vs. LD (p < 0.05), respectively. Higher values for FS and lower values for RPE were observed in the morning compared to the afternoon (p < 0.05) and in WTP vs. TP (p < 0.05). In conclusion, specific soccer skills of boys were not time-of-day dependent, but they may be associated with time pressure and task difficulty.

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