scholarly journals Effect of Fourteen Days of Acclimatization on Athletic Performance in Tropical Climate

2002 ◽  
Vol 27 (6) ◽  
pp. 551-562 ◽  
Author(s):  
Bruno Voltaire ◽  
Olivier Galy ◽  
Olivier Coste ◽  
Sébastien Racinais ◽  
André Callis ◽  
...  
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Sweat Rate ◽  
Tropical Climate ◽  
The Body ◽  
Tympanic Temperature ◽  
Body Mass Loss ◽  
Tropical Conditions ◽  
The Mean ◽  
And Performance

In order to study the acclimatization process over 14 days of exposure to tropical climate, 9 triathletes performed 4 outdoor indirect continuous multistage tests in both thermoneutral and tropical conditions. The thermoneutral test (TN, 14 °C, 45% rh) was performed before traveling to the tropical area (Martinique, FWI). The tropical tests were performed 2, 8, and 14 days after arrival (32.9 °C, 78% rh). During each trial, we measured tympanic temperature, sweat rate, body mass loss, heart rate (HR), and performance. The results showed that 1) the mean tympanic temperature was greater in T2 (P < .001), T8 (P < .01) and T14 (P < .01) than in TN and significantly lower in T14 than in T2 (P < .05); 2) the mean sweat rate was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 3) the body mass loss after trials was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 4) the mean HR and HR at rest were significantly higher (P < .005) in T2 than in TN, T8, T14 and the mean HR was significantly lower (P < .05) in T14 than in the other trials; and 5) the performance time was significantly lower in T2 (P < 0.02), T8 (P < 0.03) and T14 (P < 0.05) than in TN. We concluded that 14 days of exposure to tropical climate led to changes in physiological parameters but were still insufficient to ensure complete acclimatization in well-trained athletes. The hot/wet climate induced impairment of physiological responses and performance that were still evident on the 14th day. Keywords: triathletes, aerobic performance, jet lag, dehydration, hyperthermia

Sweat rate, salt loss, and fluid intake during an intense on-ice practice in elite Canadian male junior hockey players

2008 ◽  
Vol 33 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Matthew S. Palmer ◽  
Lawrence L. Spriet
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Sodium Concentration ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Body Mass Loss ◽  
Hockey Players ◽  
Sodium Loss

Previous research in many sports suggests that losing ~1%–2% body mass through sweating impairs athletic performance. Elite-level hockey involves high-intensity bursts of skating, arena temperatures are >10 °C, and players wear protective equipment, all of which promote sweating. This study examined the pre-practice hydration, on-ice fluid intake, and sweat and sodium losses of 44 candidates for Canada’s junior men’s hockey team (mean ± SE age, 18.4 ± 0.1 y; height, 184.8 ± 0.9 cm; mass, 89.9 ± 1.1 kg). Players were studied in groups of 10–12 during 4 intense 1 h practices (13.9 °C, 66% relative humidity) on 1 day. Hydration status was estimated by measuring urine specific gravity (USG). Sweat rate was calculated from body mass changes and fluid intake. Sweat sodium concentration ([Na]) was analyzed in forehead sweat patch samples and used with sweat rate to estimate sodium loss. Over 50% of players began practice mildly hypohydrated (USG > 1.020). Sweat rate during practice was 1.8 ± 0.1 L·h–1 and players replaced 58% (1.0 ± 0.1 L·h–1) of the sweat lost. Body mass loss averaged 0.8% ± 0.1%, but 1/3 of players lost more than 1%. Sweat [Na] was 54.2 ± 2.4 mmol·L–1 and sodium loss averaged 2.26 ± 0.17 g during practice. Players drank only water during practice and replaced no sodium. In summary, elite junior hockey players incurred large sweat and sodium losses during an intense practice, but 2/3 of players drank enough to minimize body mass loss. However, 1/3 of players lost more than 1% body mass despite ready access to fluid and numerous drinking opportunities from the coaches.

scholarly journals Symposium on ‘Performance, exercise and health’ Hydration, fluids and performance

2008 ◽  
Vol 68 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Susan M. Shirreffs
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Endurance Exercise ◽  
Exercise Performance ◽  
Team Sports ◽  
Endurance Performance ◽  
The Body ◽  
Dietary Recommendations ◽  
Mental Performance ◽  
Body Mass Loss

Sweat evaporation can be a key thermoregulatory mechanism and it causes a loss of water from all compartments of the body. Hypohydration can also develop with restricted fluid intake or with intake of diuretics. Hypohydration can affect physical and/or mental performance and/or have implications for dietary recommendations. A variety of different types and modes of exercise performance can be influenced by hydration state. Reviews of the published literature are currently most conclusive for endurance exercise. Dehydration equivalent to 2% body mass loss during exercise in a hot environment (31–32°C) impairs endurance performance, but when the exercise is performed in a temperate environment (20–21°C) a 2% body mass loss appears to have a lesser and inconsequential effect. In cold environments a body mass loss >2% may be tolerable for endurance exercise. There is a less conclusive picture as to the effects of hypohydration on other types of physical performance, including strength and power activities, team sports and the skills component of many sports, and for mental performance. A number of physiological mechanisms are responsible for the effects observed. Fluid consumption can be used to attenuate the development of a water deficit or to correct it. The composition and temperature of a drink and the volume and rate of its consumption can all influence the physiological responses to ingestion and can impact on exercise performance.

Dietary sodium citrate supplementation enhances rehydration and recovery from rapid body mass loss in trained wrestlers

2012 ◽  
Vol 37 (6) ◽  
pp. 1028-1037 ◽  
Author(s):  
Saima Timpmann ◽  
Andres Burk ◽  
Luule Medijainen ◽  
Maria Tamm ◽  
Kairi Kreegipuu ◽  
...  
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Sodium Citrate ◽  
Affective State ◽  
Dietary Sodium ◽  
Upper Body ◽  
Urine Specific Gravity ◽  
Mean Power ◽  
Body Mass Loss ◽  
And Performance

This study assessed the effects of dietary sodium citrate supplementation during a 16 h recovery from 5% rapid body mass loss (RBML) on physiological functions, affective state, and performance in trained wrestlers. Sixteen wrestlers performed an upper body intermittent sprint performance (UBISP) test under three conditions: before RBML, after RBML, and after a 16 h recovery from RBML. During recovery, the subjects ate a prescribed diet supplemented with sodium citrate (600 mg·kg–1; CIT group, N = 8) or placebo (PLC group, N = 8) and drank water ad libitum. RBML reduced (p < 0.05) UBISP mean power and increased urine specific gravity (USG). Reduction in mean power was associated with changes in plasma volume (PV) (r = 0.649, p = 0.006) and USG (r = –0.553, p = 0.026). During the 16 h recovery, increases in body mass (BM) and PV were greater (p < 0.05) in the CIT group than in the PLC group. BM gain was associated with water retention in the CIT group (r = 0.899, p = 0.002) but not in the PLC group (r = 0.335, p = 0.417). Blood pH, HCO3–concentration, and base excess increased (p < 0.05) only in the CIT group. Changes in UBISP, general negative affect, and general positive affect did not differ in the two groups. In conclusion, ingestion of sodium citrate increases blood buffering capacity and PV and stimulates BM regain during a 16 h recovery from RBML in trained wrestlers. However, sodium citrate does not improve UBISP nor does it have an impact on the affective state.

scholarly journals Sauna-induced body mass loss in physically inactive young women and men

2016 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Robert Podstawski ◽  
Tomasz Boraczyński ◽  
Michał Boraczyński ◽  
Dariusz Choszcz ◽  
Stefan Mańkowski ◽  
...  
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Young Women ◽  
Body Height ◽  
The Body ◽  
Regression Equations ◽  
Full Time ◽  
Body Mass Loss ◽  
Increased Risk ◽  
Physically Inactive

SummaryStudy aim: The aim of this study was to evaluate the relationship between basic somatic features (body mass and height) and body mass loss in physically inactive young women and men exposed to thermal stress in a dry sauna.Materials and methods: The research was conducted in 2015 on 685 first-year full-time students (333 women, 352 men), aged 19–20 years old. Nude body mass was measured after the students dried off before and after using the sauna.Results: An analysis of regression equations indicated that an increase in the body mass of women and men leads to a significant increase in sauna-induced body mass loss. On the other hand, body mass loss decreased with an increase in height in women and men, but to a smaller extent. From among the tested somatic features, body height and body mass, body mass had a decisive influence on body mass loss. Body height had a minimal and statistically non-significant impact on body mass loss.Conclusions: The results of this study indicate that heavier individuals have an increased risk of dehydration and hyperthermia. Therefore, they should pay close attention to replenishing fluids lost in the sauna. The determination of body mass loss values after a visit to a dry sauna has practical significance because it supports the estimation of the fluid volume required for the maintenance of correct water balance.

scholarly journals Effect of caffeine ingestion on fluid balance during exercise in the heat and during recovery

2014 ◽  
Vol 26 (2) ◽  
pp. 43
Author(s):  
Yang Zhang ◽  
S J Carter ◽  
R E Schumacker ◽  
Y H Neggers ◽  
M D Curtner-Smith, ◽  
...  
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Fluid Balance ◽  
Recovery Period ◽  
The Body ◽  
Body Mass Loss ◽  
Caffeine Ingestion ◽  
Hot Environment ◽  
Urine Production ◽  
Randomised Controlled

Background. The effect of ingestion of a common stimulant, caffeine, on fluid balance during exercise and recovery is not fully known. Objectives. To determine the effect of caffeine on fluid balance during exercise in the heat and during a 3-hour recovery period thereafter. Methods. In a randomised, controlled design, caffeine-naive participants (N=8) pedalled on a bike to achieve 2.5% baseline body mass loss in a hot environment in four separate conditions: with (C+) or without (C–) caffeine ingestion (6 mg/kg of body mass) prior to exercise, followed by (W+) or without (W–) 100% fluid replenishment (water) of the body mass loss during a 3-hour recovery period (yielding C+W+, C+W–, C–W+ and C–W–, respectively). Results. Mean (standard deviation) urine production was not different (p>0.05) regardless of rehydration status: 230 (162) mL (C+W–) v. 168 (77) mL (C–W–); and 713 (201) mL (C+W+) v. 634 (185) mL (C–W+). For the 3-hour recovery, caffeine ingestion caused higher hypohydration during rehydration conditions (p=0.02), but practically the mean difference in the loss of body mass was only 0.2 kg. Conclusion. In practical terms, there was no evidence that caffeine ingestion in moderation would impair fluid balance during prolonged exercise in the heat or during 3 hours of recovery.

scholarly journals Influence of Hydration on Physiological Function and Performance During Trail Running in the Heat

2010 ◽  
Vol 45 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Douglas J. Casa ◽  
Rebecca L. Stearns ◽  
Rebecca M. Lopez ◽  
Matthew S. Ganio ◽  
Brendon P. McDermott ◽  
...  
Keyword(s):  
Heart Rate ◽  
Mass Loss ◽  
Body Mass ◽  
Field Studies ◽  
Body Core Temperature ◽  
Body Mass Loss ◽  
Significant Difference ◽  
Physiologic Function ◽  
And Performance ◽  
Trail Running

Abstract Context: Authors of most field studies have not observed decrements in physiologic function and performance with increases in dehydration, although authors of well-controlled laboratory studies have consistently reported this relationship. Investigators in these field studies did not control exercise intensity, a known modulator of body core temperature. Objective: To directly examine the effect of moderate water deficit on the physiologic responses to various exercise intensities in a warm outdoor setting. Design: Semirandomized, crossover design. Setting: Field setting. Patients or Other Participants: Seventeen distance runners (9 men, 8 women; age  =  27 ± 7 years, height  =  171 ± 9 cm, mass  =  64.2 ± 9.0 kg, body fat  =  14.6% ± 5.5%). Intervention(s): Participants completed four 12-km runs (consisting of three 4-km loops) in the heat (average wet bulb globe temperature  =  26.5°C): (1) a hydrated, race trial (HYR), (2) a dehydrated, race trial (DYR), (3) a hydrated, submaximal trial (HYS), and (4) a dehydrated, submaximal trial (DYS). Main Outcome Measure(s): For DYR and DYS trials, dehydration was measured by body mass loss. In the submaximal trials, participants ran at a moderate pace that was matched by having them speed up or slow down based on pace feedback provided by researchers. Intestinal temperature was recorded using ingestible thermistors, and participants wore heart rate monitors to measure heart rate. Results: Body mass loss in relation to a 3-day baseline was greater for the DYR (−4.30% ± 1.25%) and DYS trials (−4.59% ± 1.32%) than for the HYR (−2.05% ± 1.09%) and HYS (−2.0% ± 1.24%) trials postrun (P &lt; .001). Participants ran faster for the HYR (53.15 ± 6.05 minutes) than for the DYR (55.7 ± 7.45 minutes; P &lt; .01), but speed was similar for HYS (59.57 ± 5.31 minutes) and DYS (59.44 ± 5.44 minutes; P &gt; .05). Intestinal temperature immediately postrun was greater for DYR than for HYR (P &lt; .05), the only significant difference. Intestinal temperature was greater for DYS than for HYS postloop 2, postrun, and at 10 and 20 minutes postrun (all: P &lt; .001). Intestinal temperature and heart rate were 0.22°C and 6 beats/min higher, respectively, for every additional 1% body mass loss during the DYS trial compared with the HYS trial. Conclusions: A small decrement in hydration status impaired physiologic function and performance while trail running in the heat.

scholarly journals Sweat rate and fluid intake in young elite basketball players on the FIBA Europe U20 Championship

2015 ◽  
Vol 72 (12) ◽  
pp. 1063-1068 ◽  
Author(s):  
Milica Vukasinovic-Vesic ◽  
Marija Andjelkovic ◽  
Tamara Stojmenovic ◽  
Nenad Dikic ◽  
Marija Kostic ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Body Surface ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Urine Osmolarity ◽  
Sweat Loss ◽  
Body Mass Loss ◽  
Basketball Players ◽  
The Mean

Background/Aim. Previous investigations in many sports indicated that continued exercise, especially in hot environments, can cause high sweat rate and huge water and electrolyte losses, thus impairing the performance of athletes. Most these studies were conducted during training sessions, but rarely during an official competition. Therefore, the aim of our study was to determine pre- and post-competition hydration, fluid intake and sweat loss of young elite basketball players during the FIBA Europe U20 Championship. Methods. The study included 96 basketball male players, (19 ? 0.79 years) of eight national teams. Ambient temperature was 30 ? 2?C, humidity 55 ? 4% and the mean playing time in game 18.8 ? 10.5 min. The following parameters related to hydration status were measured: fluid intake, urine output, sweat rate, percent of dehydration, urine parameters (specific gravity, color and osmolarity), body mass and body surface area. Results. We found that the mean fluid intake was 1.79 ? 0.8 L/h, sweat rate 2.7 ? 0.9 L/h, urine output 55 ? 61 mL and the percentage of dehydration 0.99 ? 0.7%. According to urine osmolarity more than 75% of players were dehydrated before the game and the process continued during the game. The difference in body mass (0.9 ? 0.7 kg) before and after the game was statistically significant. There were statistically significant correlations between the sweat rate and fluid intake, urine osmolarity, body mass loss, body surface area and percentage of dehydration. Fluid intake correlated with the percentage of dehydration, body mass loss, urine specific gravity and urine color. The sweat rate, which varied between the teams, was the highest for centers when this parameter was calculated on the effective time in game. Conclusion. Most of the athletes start competition dehydrated, fail to compensate sweat loss during the game and continue to be dehydrated, regardless what kind of drink was used. These results suggest that hydration strategies must be carefully taken into account, not only by the players, but also by the coaches and the team doctors.

Protein and lipid utilization during long-term fasting in emperor penguins

1988 ◽  
Vol 254 (1) ◽  
pp. R61-R68 ◽  
Author(s):  
J. P. Robin ◽  
M. Frain ◽  
C. Sardet ◽  
R. Groscolas ◽  
Y. Le Maho
Keyword(s):  
Uric Acid ◽  
Mass Loss ◽  
Body Mass ◽  
Phase Ii ◽  
Plasma Concentrations ◽  
The Body ◽  
Phase Iii ◽  
Body Mass Loss ◽  
Emperor Penguins

The body mass of male emperor penguins is approximately 38 kg at the beginning of the 4-mo winter fast connected with breeding, and it is an estimated approximately 18 kg in leanest birds at time of spontaneous refeeding. For a 38- to 18-kg range, we investigated the changes in the rate of body mass loss, body composition, and plasma concentrations of uric acid and urea. After the first few days (phase I) a steady state (phase II) was reached in the proportions of the energy derived from proteins and lipids with proteins accounting for a constant 4%, and the remaining 96% being from lipids. The same proportions were maintained until body mass had decreased to 24 kg. Below this value the proportion of energy derived from proteins increased progressively (phase III), being 14 times higher at 18 kg than during phase II. Rate of body mass loss and plasma uric acid and urea concentrations closely reflected the changes in protein utilization: being at a low and steady value throughout phase II and increasing during phase III. Emperor penguins also fast during the spring, but for periods of only 2-3 wk. We found a 2.5 times higher value for rate of body mass loss, uric acid, and urea during spring phase II, suggesting lower effectiveness in protein sparing at that time. It may be attributed to the lower initial lipid reserves of spring birds. Would these findings be generalized to the wide variety of birds and mammals that spontaneously fast under natural conditions?(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals BODY MASS LOSS IN DRY SAUNA AND HEART RATE RESPONSE TO HEAT STRESS

2018 ◽  
Vol 24 (4) ◽  
pp. 258-262
Author(s):  
Tomasz Boraczyński ◽  
Michał Boraczyński ◽  
Robert Podstawski ◽  
Krzysztof Borysławski ◽  
Krzysztof Jankowski
Keyword(s):  
Heart Rate ◽  
Mass Loss ◽  
Body Mass ◽  
Healthy Adult ◽  
Heat Exposure ◽  
The Body ◽  
Adult Males ◽  
Body Mass Loss ◽  
Physiological Variables ◽  
Sauna Bathing

ABSTRACT Objectives: The aim of the study was to determine the effects of sauna-induced heat exposure on body mass loss (BML) and its relationships with basic anthropometric and physiological variables. Methods: The sample comprised 230 healthy adult males aged 21.0 ± 1.08 years (age range: 20.0–24.5 years). Body surface area (BSA) was determined and two groups of individuals with high BSA (BSAH; n = 58) and low BSA (BSAL; n = 74) were extracted. The intervention consisted of two 10-min dry sauna sessions separated by a 5-min interlude. Pre-, peri-, and post-sauna measures of nude body mass (BM) and heart rate (HR) were taken. Results: BML differed between BSA groups by 0.28 kg (74.81%). Absolute and relative BML most strongly correlated with BM and BSA (p < 0.001). Among the four considered height–weight indexes, the Quetelet I Index and Body Mass Index showed the strongest associations (p < 0.001) with BML whereas the weakest were with the Rohrer Index (p < 0.01) and Slenderness Index (p < 0.05). Compared with BML, differences in HR were relatively minor (from 9.90% to 18.07%) and a significant association was observed between BML and HR at rest (p < 0.01) and in 10th and 20th min of sauna bathing (p < 0.001). Conclusions: The magnitude of BML in healthy adult males after passive heat exposure was dependent on BM and concomitantly BSA. The physiological cost of dry sauna-induced thermal strain (as assessed by BML and HR) is greater in individuals with high BM and BSA. BM and HR monitoring is also recommended in order to minimize the risk of homeostatic imbalance and cardiovascular events and this cohort should more frequently cool the body and consume a greater volume of fluids during sauna bathing. Evidence Level II; Prospective comparative study.

Body-Mass Loss, Utilization of Blubber and Fat, and Energetic Requirements of Male Southern Elephant Seals, Mirounga-Leonina, During the Molting Fast

1992 ◽  
Vol 40 (3) ◽  
pp. 235 ◽  
Author(s):  
DJ Slip ◽  
NJ Gales ◽  
HR Burton
Keyword(s):  
Energy Expenditure ◽  
Mass Loss ◽  
The Body ◽  
Relative Distribution ◽  
Mirounga Leonina ◽  
Body Mass Loss ◽  
Elephant Seals ◽  
Southern Elephant Seals ◽  
The Mean ◽  
Body Energy

The energetic requirements of male southern elephant seals, Mirounga leonina, were estimated from mass loss, and changes in blubber mass determined by ultrasound in 11 seals over the moulting fast. Mean rate of mass loss was 9.60+/-2.25 kg day-1 or 6.46+/-0.77 g kg-1 day-1, with about 63% of this lost as fat. Blubber was depleted by about 48% over the moulting period. The relative distribution of blubber remained unchanged after the moult, and seals lost blubber at similar rates over all areas of the body. Energy expenditure was estimated to be 7.54+/-82 MJ kg-1 over the mean 35.6-day moulting period.

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