Water and Salt Balance of Well-Trained Swimmers in Training

2009 ◽  
Vol 19 (6) ◽  
pp. 598-606 ◽  
Author(s):  
Ronald J. Maughan ◽  
Lisa A. Dargavel ◽  
Rachael Hares ◽  
Susan M. Shirreffs
Keyword(s):  
Body Mass ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Electrolyte Balance ◽  
Intensive Training ◽  
Males And Females ◽  
Water And Salt Balance ◽  
Sweat Composition

This study investigated fluid and electrolyte balance in well-trained male and female swimmers during 2 training sessions. Participants were 17 nationally ranked swimmers measured during a period of intensive training. Sweat loss was assessed from changes in body mass after correction for fluid intake and urine collection. Sweat composition was measured from waterproof absorbent patches applied at 4 skin sites. Air and pool-water temperatures were 36 °C and 27.4 °C, respectively. Training lasted 105 min in each session. All measured variables were similar on the 2 testing days. Mean sweat-volume loss was 548 ± 243 ml, and mean sweat rate was 0.31 ± 0.1 L/hr. Mean fluid intake was 489 ± 270 ml. Mean body-mass loss was 0.10 ± 0.50 kg, equivalent to 0.1% ± 0.7% dehydration. Mean pretraining urine osmolality was 662 ± 222 mOsm/kg, which was negatively associated with both mean drink volume consumed (p = .044, r2 = .244) and mean urine volume produced during training (p = .002, r2 = .468). Mean sweat Na+, K+, and Cl− concentrations (mmol/L) were 43 ± 14, 4 ± 1, and 31± 9, respectively; values were not different between males and females and were not different between days except for a marginal difference in K+ concentration. The average swimmer remained hydrated during the session, and calculated sweat rates were similar to those in previous aquatic studies.

scholarly journals Racial and Sex Differences in 24 Hour Urinary Hydration Markers among Male and Female Emerging Adults: A Pilot Study

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1068 ◽  
Author(s):  
William M. Adams ◽  
Derek J. Hevel ◽  
Jaclyn P. Maher ◽  
Jared T. McGuirt
Keyword(s):  
College Students ◽  
Emerging Adults ◽  
Fluid Intake ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Urine Specific Gravity ◽  
Urine Color ◽  
Males And Females ◽  
Race Ethnicity ◽  
Hispanic White

The purpose of this study was to examine 24 h urinary hydration markers in non-Hispanic White (WH) and non-Hispanic Black (BL) males and females. Thirteen males (BL, n = 6; WH, n = 7) and nineteen females (BL, n = 16, WH, n = 3) (mean ± SD; age, 20 ± 4 y; height, 169.2 ± 12.2 cm; body mass, 71.3 ± 12.2 kg; body fat, 20.8 ± 9.7%) provided a 24 h urine sample across 7 (n = 13) or 3 (n = 19) consecutive days (148 d total) for assessment of urine volume (UVOL), urine osmolality (UOSM), urine specific gravity (USG), and urine color (UCOL). UVOL was significantly lower in BL (0.85 ± 0.43 L) compared to WH college students (2.03 ± 0.70 L) (p < 0.001). Measures of UOSM, USG, and UCOL, were significantly greater in BL (716 ± 263 mOsm∙kg−1, 1.020 ± 0.007, and 4.2 ± 1.4, respectively) compared to WH college students (473 ± 194 mOsm∙kg−1, 1.013 ± 0.006, 3.0 ± 1.2, and respectively) (p < 0.05). Differences in 24 h urinary hydration measures were not significantly different between males and females (p > 0.05) or between the interaction of sex and race/ethnicity (p > 0.05). Non-Hispanic Black men and women were inadequately hydrated compared to their non-Hispanic White counterparts. Our findings suggest that development of targeted strategies to improve habitual fluid intake and potentially overall health are needed.

scholarly journals Fluid Balance and Sodium Losses During Indoor Tennis Match Play

2011 ◽  
Vol 21 (6) ◽  
pp. 492-500 ◽  
Author(s):  
Matthew J.E. Lott ◽  
Stuart D.R. Galloway
Keyword(s):  
Heart Rate ◽  
Body Mass ◽  
Fluid Balance ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Fluid Replacement ◽  
Whole Body ◽  
Electrolyte Balance ◽  
Match Play ◽  
Tennis Match

This study assessed fluid balance, sodium losses, and effort intensity during indoor tennis match play (17 ± 2 °C, 42% ± 9% relative humidity) over a mean match duration of 68.1 ± 12.8 min in 16 male tennis players. Ad libitum fluid intake was recorded throughout the match. Sweat loss from change in nude body mass; sweat electrolyte content from patches applied to the forearm, calf, and thigh, and back of each player; and electrolyte balance derived from sweat, urine, and daily food-intake analysis were measured. Effort intensity was assessed from on-court heart rate compared with data obtained during a maximal treadmill test. Sweat rate (M ± SD) was 1.1 ± 0.4 L/hr, and fluid-ingestion rate was 1.0 ± 0.6 L/hr (replacing 93% ± 47% of fluid lost), resulting in only a small mean loss in body mass of 0.15% ± 0.74%. Large interindividual variabilities in sweat rate (range 0.3–2.0 L/hr) and fluid intake (range 0.31–2.52 L/hr) were noted. Whole-body sweat sodium concentration was 38 ± 12 mmol/L, and total sodium losses during match play were 1.1 ± 0.4 g (range 0.5–1.8 g). Daily sodium intake was 2.8 ± 1.1 g. Indoor match play largely consisted of low-intensity exercise below ventilatory threshold (mean match heart rate was 138 ± 24 beats/min). This study shows that in moderate indoor temperature conditions players ingest sufficient fluid to replace sweat losses. However, the wide range in data obtained highlights the need for individualized fluid-replacement guidance.

On-ice sweat rate, voluntary fluid intake, and sodium balance during practice in male junior ice hockey players drinking water or a carbohydrate–electrolyte solution

2010 ◽  
Vol 35 (3) ◽  
pp. 328-335 ◽  
Author(s):  
Matthew S. Palmer ◽  
Heather M. Logan ◽  
Lawrence L. Spriet
Keyword(s):  
Body Mass ◽  
Electrolyte Solution ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Sodium Concentration ◽  
Ice Hockey ◽  
Sodium Balance ◽  
Sweat Test ◽  
Electrolyte Balance ◽  
Hockey Players

This study evaluated the repeatability of hydration and sweat measurements taken during on-ice hockey practices with players drinking only water, and determined whether having only a carbohydrate–electrolyte solution (CES) to drink during practices decreased fluid intake or affected other hydration and (or) sweat measures. All testing was conducted on elite players of an Ontario Hockey League team (±SE; mean age, 17.6 ± 0.3 years; mean height, 182.9 ± 1.4 cm; mean body mass, 83.0 ± 1.7 kg). Players were studied 3 times over the course of 6 weekly on-ice practices (±SE; mean playing time, 1.58 ± 0.07 h; mean temperature, 11.4 ± 0.8 °C; mean relative humidity, 52% ± 3%). There was strong repeatability of the measured hydration and sweat parameters between 2 similar on-ice practices when players drank only water. Limiting the players to drinking only a CES (as opposed to water) did not decrease fluid intake during practice (±SE; mean CES intake, 0.72 ± 0.07 L·h–1 vs. mean water intake, 0.82 ± 0.08 L·h–1) or affect sweat rate (1.5 ± 0.1 L·h–1 vs. 1.5 ± 0.1 L·h–1), sweat sodium concentration (72.4 ± 5.6 mmol·L–1 vs. 73.0 ± 4.4 mmol·L–1), or percent body mass loss (1.1% ± 0.2% vs. 0.9% ± 0.2%). Drinking a CES also improved sodium balance (–2.1 ± 0.2 g·h–1 vs. –2.6 ± 0.3 g·h–1) and provided the players with a significant carbohydrate (43 ± 4 g·h–1 vs. 0 ± 0 g·h–1) during practice. In summary, a single field sweat test during similar on-ice hockey practices in male junior hockey players is sufficient to evaluate fluid and electrolyte balance. Also, a CES does not affect voluntary fluid intake during practice, compared with water, in these players. The CES provided some salt to offset the salt lost in sweat, and carbohydrate, which may help maintain physical and mental performance in the later stages of practice.

scholarly journals Effects of a 14-Day Hydration Intervention on Individuals with Habitually Low Fluid Intake

2021 ◽  
Author(s):  
Aaron R. Caldwell ◽  
Megan E. Rosa-Caldwell ◽  
Carson Keeter ◽  
Evan C. Johnson ◽  
François Péronnet ◽  
...  
Keyword(s):  
Body Weight ◽  
Total Body Water ◽  
Fluid Intake ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Body Water ◽  
Control Group ◽  
Intervention Phase ◽  
Total Body ◽  
Experimental Group

<b><i>Background:</i></b> Debate continues over whether or not individuals with low total water intake (TWI) are in a chronic fluid deficit (i.e., low total body water) [<xref ref-type="bibr" rid="ref1">1</xref>]. When women with habitually low TWI (1.6 ± 0.5 L/day) increased their fluid intake (3.5 ± 0.1 L/day) for 4 days 24-h urine osmolality decreased, but there was no change in body weight, a proxy for total body water (TBW) [<xref ref-type="bibr" rid="ref2">2</xref>]. In a small (<i>n</i> = 5) study of adult men, there were no observable changes in TBW, as measured by bioelectrical impedance, after increasing TWI for 4 weeks [<xref ref-type="bibr" rid="ref3">3</xref>]. However, body weight increased and salivary osmolality decreased indicating that the study may have been underpowered to detect changes in TBW. Further, no studies to date have measured changes in blood volume (BV) when TWI is increased. <b><i>Objectives:</i></b> Therefore, the purpose of this study was to identify individuals with habitually low fluid intake and determine if increasing TWI, for 14 days, resulted in changes in TBW or BV. <b><i>Methods:</i></b> In order to identify individuals with low TWI, 889 healthy adults were screened. Participants with a self-reported TWI less than 1.8 L/day (men) or 1.2 L/day (women), and a 24-h urine osmolality greater than 800 mOsm were included in the intervention phase of the study. For the intervention phase, 15 participants were assigned to the experimental group and 8 participants were assigned to the control group. The intervention period lasted for 14 days and consisted of 2 visits to our laboratory: one before the intervention (baseline) and 14 days into the intervention (14-day follow-up). At these visits, BV was measured using a CO-rebreathe procedure and deuterium oxide (D<sub>2</sub>O) was administered to measure TBW. Urine samples were collected immediately prior, and 3–8 h after the D<sub>2</sub>O dose to allow for equilibration. Prior to each visit, participants collected 24-h urine to measure 24-h hydration status. After the baseline visit, the experimental group increased their TWI to 3.7 L for males and 2.7 L for females in order to meet the current Institute of Medicine recommendations for TWI. <b><i>Results:</i></b> Twenty-four-hour urine osmolality decreased (−438.7 ± 362.1 mOsm; <i>p</i> &#x3c; 0.001) and urine volume increased (1,526 ± 869 mL; <i>p</i> &#x3c; 0.001) in the experimental group from baseline, while there were no differences in osmolality (−74.7 ± 572 mOsm; <i>p</i> = 0.45), or urine volume (−32 ± 1,376 mL; <i>p</i> = 0.89) in the control group. However, there were no changes in BV (Fig. <xref ref-type="fig" rid="f01">1</xref>a) or changes in TBW (Fig. <xref ref-type="fig" rid="f01">1</xref>b) in either group. <b><i>Conclusions:</i></b> Increasing fluid intake in individuals with habitually low TWI increases 24-h urine volume and decreases urine osmolality but does not result in changes in TBW or BV. These findings are in agreement with previous work indicating that TWI interventions lasting 3 days [<xref ref-type="bibr" rid="ref2">2</xref>] to 4 weeks [<xref ref-type="bibr" rid="ref3">3</xref>] do not result in changes in TBW. Current evidence would suggest that the benefits of increasing TWI are not related changes in TBW.

scholarly journals Small Differences in Everyday Hydration Status Influence Mood (P04-134-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
David Benton ◽  
Alecia Cousins ◽  
Hayley Young
Keyword(s):  
Body Mass ◽  
Psychological Functioning ◽  
Fluid Intake ◽  
Urine Osmolality ◽  
Normal Diet ◽  
Hydration Status ◽  
Funding Sources ◽  
Lower Baseline ◽  
Urine Production ◽  
The Impact

Abstract Objectives Reviews consistently find that a loss of about 2% of body mass was needed before either athletic or psychological functioning is disrupted. However, although it is usually assumed that the minor changes in hydration status, that occur during normal life, do not impact on performance, experimentally the topic has been virtually ignored. The impact of everyday variations in hydration was therefore examined. Methods 168 subjects were randomly allocated to drinking water, or not drinking, and in addition consume capsules containing either 300 mg of sodium chloride or a placebo. Subjects were monitored over a three-hour period, during which urine osmolality, loss of body mass and urine production were monitored. Repeatedly subjects reported their mood. Results Subjects came having consumed their normal diet, without any restriction on fluid intake: on average 0.5% body mass was lost during the study. The major finding was that the hydration status on arrival had a greater influence, than subsequent fluid intake and changes in osmolality during the study. With ratings of being agreeable rather than hostile, those with lower baseline osmolality who drank water had better mood than if baseline osmolality was high. As another example, the mood of those who did not drink water only declined during the study when baseline osmolality was high rather than low. With measures of being composed rather than anxious, and being confidence rather than unsure, those who had lower baseline osmolality had a better mood, irrespective of whether water was consumed. Thus, baseline osmolality had an impact greater than drink induced changes in osmolality. Traditionally the normal range of urine osmolality has been said to be 200–800 mOsmoles/kg, yet the critical point at which the response to fluid intake changed was 600 mOsmoles/kg: 61% had a baseline osmolality over 600 and 38% over 800 mOsmoles/kg. Conclusions Some individuals are in a state of dehydration that adversely influences mood; a state not reversed by acute fluid consumption. The pattern of consumption associated with mild-dehydration and its functional consequences needs to be established. Funding Sources There was no funding external other than provided by ** University.

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.

Age and regulation of fluid and electrolyte balance during repeated exercise sessions

1996 ◽  
Vol 270 (1) ◽  
pp. R71-R79 ◽  
Author(s):  
D. H. Zappe ◽  
G. W. Bell ◽  
H. Swartzentruber ◽  
R. F. Wideman ◽  
W. L. Kenney
Keyword(s):  
Fluid Intake ◽  
Maximal Oxygen Consumption ◽  
Urine Osmolality ◽  
Urinary Sodium Excretion ◽  
Electrolyte Balance ◽  
Similar Response ◽  
Older Individuals ◽  
Warm Environment ◽  
Repeated Exercise ◽  
Exercise Period

A common response after only 3-4 days of repeated exercise in younger individuals is an expansion of plasma volume (PV); however, it is not known if older individuals have a similar response. In this study, six older (O) (67 +/- 1 yr) and six younger (Y) men (24 +/- 2 yr) cycled for 4 successive days at 50% maximal oxygen consumption (Vo2max) for 90 min in a warm environment [30 degrees C temperature dry bulb (Tdb), 24 degrees C temperature wet bulb (Twb)]. On day 4, PV was increased (P < 0.05) in Y (10.0 +/- 1%) but not (P > 0.05) in O (1.7 +/- 2%). The increased PV was associated with a greater (P < 0.05) daily fluid intake during the exercise period in Y (45 +/- 3 ml. day-1.kg body wt-1) compared with O (32 +/- 2 ml.day-1.kg body wt-1) and an increase (P < 0.05) in the total circulating protein (TCP) content in Y (0.23 +/- 0.1 g/kg body wt) but not in O (0.10 +/- 0.1 g/kg body wt). Throughout the 4-day exercise period there were similar reductions in 24-h urine flow rate (UV) and urinary sodium excretion (UNaV) in Y and O. Additionally, acute renal clearance measures made during exercise on days 1 and 4 showed similar (P > 0.05) reductions in UNaV between Y (-55 +/- 10%) and O (-44 +/- 6%). However, during exercise in O there were no changes (P > 0.05) in UV (2 +/- 12%) and urine osmolality (UOsm) (-12 +/- 6%) from resting values compared with Y, where UV was decreased (P < 0.05) by 41 +/- 9% and UOsm was increased (P < 0.05) by 39 +/- 8%. Therefore, the inability of the older subjects to increase PV after repeated days of exercise is not related to an impaired renal fluid and Na+ conservation ability, despite a reduced urine concentrating ability during exercise, but to other factors (e.g., fluid intake and TCP) that appear necessary for the hypervolemic response.

Development of Individual Hydration Strategies for Athletes

2008 ◽  
Vol 18 (5) ◽  
pp. 457-472 ◽  
Author(s):  
Ronald J. Maughan ◽  
Susan M. Shirreffs
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Environmental Conditions ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Hydration Status ◽  
Additional Information ◽  
Urine Color ◽  
Individual Needs ◽  
Exercise Environment

Athletes are encouraged to begin exercise well hydrated and to consume sufficient amounts of appropriate fluids during exercise to limit water and salt deficits. Available evidence suggests that many athletes begin exercise already dehydrated to some degree, and although most fail to drink enough to match sweat losses, some drink too much and a few develop hyponatremia. Some simple advice can help athletes assess their hydration status and develop a personalized hydration strategy that takes account of exercise, environment, and individual needs. Preexercise hydration status can be assessed from urine frequency and volume, with additional information from urine color, specific gravity, or osmolality. Change in hydration during exercise can be estimated from the change in body mass that occurs during a bout of exercise. Sweat rate can be estimated if fluid intake and urinary losses are also measured. Sweat salt losses can be determined by collection and analysis of sweat samples, but athletes losing large amounts of salt are likely to be aware of the taste of salt in sweat and the development of salt crusts on skin and clothing where sweat has evaporated. An appropriate drinking strategy will take account of preexercise hydration status and of fluid, electrolyte, and substrate needs before, during, and after a period of exercise. Strategies will vary greatly between individuals and will also be influenced by environmental conditions, competition regulations, and other factors.

scholarly journals The effects of fasting in Ramadan

1978 ◽  
Vol 40 (3) ◽  
pp. 583-589 ◽  
Author(s):  
K. Y. Mustafa ◽  
N. A. Mahmoud ◽  
K. A. Gumaa ◽  
A. M. A. Gader
Keyword(s):  
Young Adults ◽  
Fluid Balance ◽  
Water Loss ◽  
Fluid Intake ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Good Control ◽  
Urine Osmolality ◽  
Urine Concentration ◽  
Evaporative Water

1. Fluid intake, urine output and evaporative water loss were measured and fluid balance calculated in sixteen subjects for 1 d before Ramadan, during weeks 1–5 of fasting and on the 10th day after the end of Ramadan.2. Plasma osmolality at 06.00 hours, the beginning of the fast, at 18.00 hours, before breaking the fast and at 19.00 hours, 1 h after breaking the fast, and urine osmolality during the day and night were measured before, during and after Ramadan.3. All subjects developed an initial negative fluid balance which was maximum at the beginning of week 3 of fasting and that deficit was compensated for during the later weeks.4. Compensation was brought about by an increase in urine concentration, a decrease in urine volume by day, and salt retention.5. No significant changes were observed in plasma osmolality during the days of fasting and the ‘setting’ of plasma osmolality during Ramadan also was not changed.6. It was concluded that healthy young adults maintain good control of fluid and electroytes during Ramadan.

scholarly journals Relative Validity of a Beverage Frequency Questionnaire Used to Assess Fluid Intake in the Autosomal Dominant Polycystic Kidney Disease Population

Nutrients ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1051
Author(s):  
Carly Mannix ◽  
Anna Rangan ◽  
Annette Wong ◽  
Jennifer Zhang ◽  
Margaret Allman-Farinelli ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Fluid Intake ◽  
Autosomal Dominant ◽  
Pearson Correlation ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Validity And Reliability ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney

Maintaining hydration sufficient to reduce levels of arginine vasopressin has been hypothesised to slow kidney cyst growth in autosomal dominant polycystic kidney disease (ADPKD). The semi-quantitative beverage frequency questionnaire (BFQ) was designed to measure usual fluid intake over the past month. The aim of this study was to assess the validity and reliability of the BFQ compared with the 24-h urine biomarkers. Participants with ADPKD (18–67 years; estimated glomerular filtration rate (eGFR) ≥ 30 mL/min1.73 m2) completed the BFQ. Serum creatinine, eGFR, 24-h urine volume, and osmolality were measured. Pearson correlation coefficients, paired t test, and Bland–Altman plots were used to evaluate agreement between the methods. A subset repeated the BFQ to assess reliability. A total of 121 participants (54% male, 43 ± 11 years; mean ± SD) completed the BFQ and at least one 24-h urine collection. The correlation between the BFQ and the 24-h urine volume was moderate (r = 0.580) and weaker with the 24-h urine osmolality (r = −0.276). The Bland–Altman plots revealed good agreement between the BFQ and the 24-h urine volume with no obvious bias; however, the limits of agreement were wide (−1517–1943 mL). The BFQ1 and BFQ2 were strongly correlated (r = 0.799, p < 0.001) and were not significantly different (p = 0.598). The BFQ is a valid and reliable tool to assess the usual fluid intake of the ADPKD population.

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