Water and electrolyte shifts with partial fluid replacement during exercise

Sanders, Barry; Noakes, Timothy D.; Dennis, Steven C.

doi:10.1007/s004210050598

Cited by 41 publications

(31 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our group has much experience with ISEs, from developing new ionophores to their application including environmental, industrial and physiological measurements 18,[32][33][34][35][36] . One of the most successful of these ionophores is a calix [4]arene based sodium ionophore (Sigma), which we use in the SSB.…”

Section: Resultsmentioning

confidence: 99%

“…Dehydration for example can manifest itself as an increased sodium concentrations in sweat during exercise, so the possibility of monitoring this quantitatively in real-time is an appealing prospect 1 . Currently, for studies involving athletic performance, instead of directly analysing specific electrolyte concentrations, available fluid volumes are usually inferred only from body weight loss and urine output volumes over a set period of exercise, with electrolyte concentrations only measured separately and retrospectively [2][3][4][5] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

Schazmann¹,

et al. 2010

View full text Add to dashboard Cite

We report a new easier method for the quantitative analysis of sodium in human sweat. To the best of our knowledge this is the first time this has been done successfully in a real-time manner. We consolidate sweat stimulation, collection and analysis functions into a single method. This temporal data opens up new possibilities in the study of human physiology, broadly applicable from assessing athletic performance and hydration levels to monitoring Cystic Fibrosis (CF) sufferers. Our compact Sodium Sensor Belt (SSB) consists of a sodium selective Ion Selective Electrode (ISE) integrated into a platform that can be interfaced with the human body during exercise. No skin cleaning regime or sweat storage technology is required as samples is continually wicked from skin to a sensing surface and on to a waste terminal via a fabric pump. After an initial equilibration period, a sodium plateau concentration was reached and monitored continuously. Atomic Absorption Spectroscopy (AAS) was used as a refe rence method, confirming accuracy. The plateau concentrations observed fell within expected literature ranges, further confirming accuracy. Daily calibration 2 repeatability (n=4) was ±3.0% RSD and over a three month period reproducibility was ±12.1% RSD (n=56). As a further application, we attempted to monitor the sweat of Cystic Fibrosis (CF) sufferers using the same device. We observed high sodium concentrations symptomatic of CF (~60mM Na + ) for 2 CF patients, with no conclusive results for the remaining patients due to their limited exercising capability. The real-time monitoring of hydration levels during physical exercise for health and performance purposes is a particularly promising application for the SSB at present.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

Schazmann¹,

et al. 2010

View full text Add to dashboard Cite

show abstract

“…However, studies at ultra-endurance races such as an Ironman triathlon showed that oral sodium supplementation was not necessary to prevent hyponatremia (Hew-Butler et al 2006;Speedy et al 2002). Also sodium ingestion may not be of much advantage when athletes replace only *50% of their fluid loss during performances at 32°C (Sanders et al 1999). Sodium supplementation might, however, be of importance in a hot environment.…”

Section: Discussionmentioning

confidence: 96%

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

Knechtle

Knechtle²,

Rosemann

2010

Eur J Appl Physiol

View full text Add to dashboard Cite

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 145 male ultra-marathoners at the '100-km ultra-run' in Biel, Switzerland. Changes in body mass, urinary specific gravity, haemoglobin, haematocrit, plasma [Na(+)], and plasma volume were determined. Seven runners (4.8%) developed asymptomatic EAH. Body mass, haematocrit and haemoglobin decreased, plasma [Na(+)] remained unchanged and plasma volume increased. Δ body mass correlated with both post race plasma [Na(+)] and Δ plasma [Na(+)]. Δ plasma volume was associated with post race plasma [Na(+)]. The athletes consumed 0.65 (0.30) L/h; fluid intake correlated significantly and negatively (r = -0.50, p < 0.0001) to race time. Fluid intake was neither associated with post race plasma [Na(+)] nor with Δ plasma [Na(+)], but was related to Δ body mass. To conclude, the prevalence of EAH was low at ~5% in these male 100 km ultra-marathoners. EAH was asymptomatic and would not have been detected without the measurement of plasma [Na(+)].

show abstract

“…Moreover, variations in urine specific gravity and osmolality lag behind rapid changes in sweat losses or fluid intake (42). Besides having a potential influence on urine hydration status measures, CHO-E also may have enhanced (compared with water) total body hydration by ensuring greater fluid retention and distribution to all fluid compartments (30,31,50,51) and may have contributed to minimizing T C and cardiovascular strain during bout 2 (9).…”

Section: Repeated-bout Exercise In the Heat In Young Athletesmentioning

confidence: 99%

Repeated-bout exercise in the heat in young athletes: physiological strain and perceptual responses

Bergeron¹,

Laird²,

Marinik³

et al. 2009

Journal of Applied Physiology

View full text Add to dashboard Cite

A short recovery period between same-day competitions is common practice in organized youth sports. We hypothesized that young athletes will experience an increase in physiological strain and perceptual discomfort during a second identical exercise bout in the heat, with 1 h (21°C) between bouts, even with ample hydration. Twenty-four athletes (6 boys and 6 girls: 12-13 yr old, 47.7 Ϯ 8.3 kg; 6 boys and 6 girls: 16 -17 yr old, 61.0 Ϯ 8.6 kg) completed two 80-min intermittent exercise bouts (treadmill 60%, cycle 40% peak oxygen uptake) in the heat (33°C, 48.9 Ϯ 6.1% relative humidity). Sweat loss during each bout was similar within each age group (12-13 yr old: bout 1, 943.6 Ϯ 237.1 ml; bout 2, 955.5 Ϯ 250.3 ml; 16 -17 yr old: bout 1, 1,382.2 Ϯ 480.7 ml; bout 2, 1,373.1 Ϯ 472.2 ml). Area under the curve (AUC) was not statistically different (P Ͼ 0.05) between bouts for core body temperature (12-13 yr old: bout 1 peak, 38.6 Ϯ 0.4°C; bout 2, 38.4 Ϯ 0.2°C; 16 -17 yr old: bout 1 peak, 38.8 Ϯ 0.7°C; bout 2, 38.7 Ϯ 0.6°C), physiological strain index (12-13 yr old: bout 1 peak, 7.9 Ϯ 0.9; bout 2, 7.5 Ϯ 0.7; 16 -17 yr old: bout 1 peak, 8.1 Ϯ 1.5; bout 2, 7.9 Ϯ 1.4), or thermal sensation for any age/sex subgroup or for all subjects combined. However, rating of perceived exertion AUC and peak were higher (P ϭ 0.0090 and 0.0004, respectively) during bout 2 in the older age group. Notably, four subjects experienced consistently higher responses throughout bout 2. With these healthy, fit, young athletes, 1 h of complete rest, cool down, and rehydration following 80 min of strenuous exercise in the heat was generally effective in eliminating any apparent carryover effects that would have resulted in greater thermal and cardiovascular strain during a subsequent identical exercise bout. hydration; recovery; risk management; thermoregulation; youth sports A SHORT RECOVERY PERIOD between same-day rounds of tournament competition is common practice in organized youth sports. With the additional effects imposed by a hot environment on cardiovascular and thermal strain, performance, and exertional heat injury risk (1,2,4,8,9,14,21,22,24,25,45,47,48), the ability to perform safely and effectively through multiple strenuous same-day competition bouts in the heat can be challenging for young athletes (8, 16). The apparent cumulative demands can often result in poor performance or complete withdrawal from play. Wallace et al. (58) found that exertional heat illness risk was more strongly associated with the combined effects of previous-day wet bulb globe temperature (WBGT) and current-day heat exposure than with either measure alone, suggesting a cumulative effect on thermal strain during exercise in the field. With same-day exercise, Ronsen et al. (46) found that a longer recovery period between bouts (6 vs. 3 h) attenuated the degree of increased metabolic stress and cardiovascular and thermal strain in the second exercise bout for elite endurance athletes, demonstrating how the extent of residual or carryover effects from a previous ...

show abstract

Water and electrolyte shifts with partial fluid replacement during exercise

Cited by 41 publications

References 31 publications

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

Repeated-bout exercise in the heat in young athletes: physiological strain and perceptual responses

Contact Info

Product

Resources

About