scholarly journals A Case-Series Observation of Sweat Rate Variability in Endurance-Trained Athletes

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1807
Author(s):  
JohnEric W. Smith ◽  
Marissa L. Bello ◽  
Ffion G. Price
Keyword(s):  
Body Mass ◽  
Environmental Conditions ◽  
Sweat Rate ◽  
Case Series ◽  
Exercise Duration ◽  
Fluid Replacement ◽  
Fluid Consumption ◽  
Series Design ◽  
Consumption Data ◽  
Similar Temperature

Adequate fluid replacement during exercise is an important consideration for athletes, however sweat rate (SR) can vary day-to-day. The purpose of this study was to investigate day-to-day variations in SR while performing self-selected exercise sessions to evaluate error in SR estimations in similar temperature conditions. Thirteen endurance-trained athletes completed training sessions in a case-series design 1x/week for a minimum 30 min of running/biking over 24 weeks. Body mass was recorded pre/post-training and corrected for fluid consumption. Data were split into three Wet-Bulb Globe Thermometer (WBGT) conditions: LOW (<10 °C), MOD (10–19.9 °C), HIGH (>20 °C). No significant differences existed in exercise duration, distance, pace, or WBGT for any group (p > 0.07). Significant differences in SR variability occurred for all groups, with average differences of: LOW = 0.15 L/h; MOD = 0.14 L/h; HIGH = 0.16 L/h (p < 0.05). There were no significant differences in mean SR between LOW-MOD (p > 0.9), but significant differences between LOW-HIGH and MOD-HIGH (p < 0.03). The assessment of SR can provide useful data for determining hydration strategies. The significant differences in SR within each temperature range indicates a single assessment may not accurately represent an individual’s typical SR even in similar environmental conditions.

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.

scholarly journals Fluid Consumption and Sweating in National Football League and Collegiate Football Players With Different Access to Fluids During Practice

2010 ◽  
Vol 45 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Sandra Fowkes Godek ◽  
Arthur R. Bartolozzi ◽  
Chris Peduzzi ◽  
Scott Heinerichs ◽  
Eugene Garvin ◽  
...  
Keyword(s):  
National Football League ◽  
National Collegiate Athletic Association ◽  
Sweat Rate ◽  
Fluid Replacement ◽  
Football Players ◽  
Fluid Consumption ◽  
Sweat Loss ◽  
Sports Drinks ◽  
Football Team ◽  
Collegiate Football

Abstract Context: Considerable controversy regarding fluid replacement during exercise currently exists. Objective: To compare fluid turnover between National Football League (NFL) players who have constant fluid access and collegiate football players who replace fluids during water breaks in practices. Design: Observational study. Setting: Respective preseason training camps of 1 National Collegiate Athletic Association Division II (DII) football team and 1 NFL football team. Both morning and afternoon practices for DII players were 2.25 hours in length, and NFL players practiced for 2.25 hours in the morning and 1 hour in the afternoon. Environmental conditions did not differ. Patients or Other Participants: Eight NFL players (4 linemen, 4 backs) and 8 physically matched DII players (4 linemen, 4 backs) participated. Intervention(s): All players drank fluids only from their predetermined individual containers. The NFL players could consume both water and sports drinks, and the DII players could only consume water. Main Outcome Measure(s): We measured fluid consumption, sweat rate, total sweat loss, and percentage of sweat loss replaced. Sweat rate was calculated as change in mass adjusted for fluids consumed and urine produced. Results: Mean sweat rate was not different between NFL (2.1 ± 0.25 L/h) and DII (1.8 ± 0.15 L/h) players (F1,12  =  2, P  =  .18) but was different between linemen (2.3 ± 0.2 L/h) and backs (1.6 ± 0.2 L/h) (t14  =  3.14, P  =  .007). We found no differences between NFL and DII players in terms of percentage of weight loss (t7  =  −0.03, P  =  .98) or rate of fluid consumption (t7  =  −0.76, P  =  .47). Daily sweat loss was greater in DII (8.0 ± 2.0 L) than in NFL (6.4 ± 2.1 L) players (t7  =  −3, P  =  .02), and fluid consumed was also greater in DII (5.0 ± 1.5 L) than in NFL (4.0 ± 1.1 L) players (t7  =  −2.8, P  =  .026). We found a correlation between sweat loss and fluids consumed (r  =  0.79, P &lt; .001). Conclusions: During preseason practices, the DII players drinking water at water breaks replaced the same volume of fluid (66% of weight lost) as NFL players with constant access to both water and sports drinks.

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 Sweat rate and environmental factors in junior Laser class sailors

2020 ◽  
Vol 37 (5) ◽  
pp. 298-304
Author(s):  
GJ Lorenzo González ◽  
J Toro Prieto-Puga ◽  
T Teresa Seoane Pillado ◽  
E Fernández Windscheid
Keyword(s):  
Food Intake ◽  
Environmental Factors ◽  
Body Mass ◽  
Environmental Temperature ◽  
Sweat Rate ◽  
Weather Conditions ◽  
Fluid Replacement ◽  
Cold Weather ◽  
Body Mass Change ◽  
Target Weight

Introduction: Recent studies have reported differences in sweat rate (SR) in laser class (LC) sailors under extreme environmental conditions (EC). This study aimed to determine a ‘standard-like’ SR in junior Laser 4.7 sailors under ‘not-extreme’ weather conditions to achieve an adequate fluid replacement rate for training and racing sessions. Additionally, we analysed the hypothetical relationship between SR and certain environmental factors, not just considering them as independent variables, but also including them as a whole factor, usually known as ‘windchill’ (WCh). Material and method: Nine male elite junior Laser 4.7 class athletes were included in this descriptive study. They were monitored during the entire year of training and racing sessions, including national and international championships. Body mass changes as well as their food and fluid intake were measured for each sailor before and after sailing to estimate SR, absolute body mass change, and percentage body mass variation for all the sessions. Athletes were asked to maintain “ab libitum” fluid and food intake during the study. Environmental temperature, wind speed, and relative humidity were measured. Results: Significant differences (p = 0.012) were observed between training and racing sessions with respect to SR, 0.18 (±0.14) L.h−1 vs. 0.23 (± 0.12 L.h−1). Environmental temperature and WCh during racing showed an inverse relationship with SR. Discussion: This result suggests that increased fluid and food intake are required under cold weather conditions to maintain the ‘target’ weight during the competitions and improve performance.

scholarly journals Increasing Anticipatory Pleasure in Major Depression through Enhancing Episodic Future Thinking: A Randomized Single-Case Series Trial

2019 ◽  
Author(s):  
David John Hallford ◽  
Manoj Kumar Sharma ◽  
David W. Austin
Keyword(s):  
Major Depressive Disorder ◽  
Major Depression ◽  
Mental Imagery ◽  
Single Case ◽  
Case Series ◽  
Episodic Future Thinking ◽  
Future Thinking ◽  
Major Depressive ◽  
Positive Events ◽  
Series Design

Depressed individuals have difficulty anticipating pleasure, which can impact motivation and functioning. One factor in this may be impairments in their episodic future thinking (EFT). This study examined whether enhancing EFT through increasing detail/vividness and mental imagery would increase anticipatory pleasure among individuals with Major Depressive Disorder. A randomized start-point, single case series design was used. Depressed outpatients (N = 7) completed surveys through the day over two weeks to nominate upcoming positive events and rate them on EFT detail/vividness, mental imagery, and anticipatory pleasure. At a randomized start-point, activities to enhance the detail/vividness and mental imagery for these upcoming events were introduced. Significant increases in detail and imagery were observed when EFT activities were introduced, which correlated with increases in how pleasurable it was thought the activities would be and how pleasurable it was thinking about them. Enhancing EFT may be a mechanism to increase anticipatory pleasure in depression. Implications for treatment are discussed.

scholarly journals Smoking and Stroke in Appalachian Kentucky

2018 ◽  
pp. 1-4
Author(s):  
Dignan Mark ◽  
Dignan Mark ◽  
Kitzman Patrick ◽  
S Gutti Subhash ◽  
N Gutti Swathi ◽  
...  
Keyword(s):  
Medical Records ◽  
Case Series ◽  
Eastern Region ◽  
Retrospective Case ◽  
Series Design ◽  
Stroke Prevalence ◽  
Appalachian Kentucky ◽  
The Mean ◽  
Stroke Type ◽  
Stroke Belt

This project used a retrospective case series design to investigate factors associated with stroke in a rural area in Appalachian Kentucky. The south-eastern region of the U.S. is often referred to as the ‘stroke belt,’ and includes the Appalachian region of the state of Kentucky. Data were collected from medical records of patients from a neurology practice and regional hospital with a diagnosis of stroke from March 2012 through November 2015. Data were collected without personal identifiers and included demographic characteristics, stroke type, treatments received, and referrals for additional care including rehabilitation. Data from a total of 84 stroke cases diagnosed between March 2012 and November 2015 were included. Of the 84 cases, 46 (54.8%) were female and all but one was Caucasian. The distribution by race is consistent with the population of the region. The stroke cases ranged in age from 41 to 92 (M=66.3) and the age at stroke diagnosis ranged from 40 to 90 (M=65.7). Fourteen (16.7%) had evidence of a previous stroke at diagnosis. For smokers, the mean age at diagnosis was 62.7 for smokers while for non-smokers it was 67.5. The study reported smoking rates that were nearly three-times the national average, and the smokers in this study were found to have stroke onset approximately five-years earlier than non-smokers. The results from this case series support the need for further investigation on stroke prevalence and factors contributing to continued risk for stroke in Appalachia.

scholarly journals Risk of Infective Endocarditis After Invasive Dental Treatments

Circulation ◽  
2018 ◽  
Vol 138 (4) ◽  
pp. 356-363 ◽  
Author(s):  
Tzu-Ting Chen ◽  
Yi-Chun Yeh ◽  
Kuo-Liong Chien ◽  
Mei-Shu Lai ◽  
Yu-Kang Tu
Keyword(s):  
Infective Endocarditis ◽  
Confidence Interval ◽  
Regression Model ◽  
Conditional Logistic Regression ◽  
Case Series ◽  
Crossover Design ◽  
The Self ◽  
Series Design ◽  
Case Crossover ◽  
Study Designs

Background: Invasive dental treatments (IDTs) can yield temporary bacteremia and have therefore been considered a potential risk factor of infective endocarditis (IE). It is hypothesized that, through the trauma caused by IDTs, bacteria gain entry to the bloodstream and may attach to abnormal heart valves or damaged heart tissue, giving rise to IE. However, the association between IDTs and IE remains controversial. The aim of this study is to estimate the association between IDTs and IE. Methods: The data in this study were obtained from the Health Insurance Database in Taiwan. We selected 2 case-only study designs, case-crossover and self-controlled case series, to analyze the data. The advantage of these methods is that confounding factors that do not vary with time are adjusted for implicitly. In the case-crossover design, a conditional logistic regression model with exposure to IDTs was used to estimate the risks of IE following an IDT with 4, 8, 12, and 16 weeks delay, respectively. In the self-controlled case series design, a conditional Poisson regression model was used to estimate the risk of IE for the risk periods of 1 to 4, 5 to 8, 9 to 12, and 13 to 16 weeks following an IDT. Results: In total, 9120 and 8181 patients with IE were included in case-crossover design and self-controlled case series design, respectively. In the case-crossover design, 277 cases and 249 controls received IDTs during the exposure period, and the odds ratio was 1.12 (95% confidence interval, 0.94–1.34) for 4 weeks. In the self-controlled case series design, we observed that 407 IEs occurred during the first 4 weeks after IDTs, and the age-adjusted incidence rate ratio was 1.14 (95% confidence interval, 1.02–1.26) for 1 to 4 weeks after IDTs. Conclusions: In both study designs, we did not observe a clinically larger risk for IE in the short periods after IDTs. We also found no association between IDTs and IE among patients with a high risk of IE. Therefore, antibiotic prophylaxis for the prevention of IE is not required for the Taiwanese population.

scholarly journals Risks of suicide attempts after prescription of zolpidem in people with depression: a nationwide population study in South Korea

SLEEP ◽  
2019 ◽  
Vol 43 (3) ◽  
Author(s):  
Hyewon Kim ◽  
Yuwon Kim ◽  
Woojae Myung ◽  
Maurizio Fava ◽  
David Mischoulon ◽  
...  
Keyword(s):  
Suicide Attempt ◽  
Medical Records ◽  
Suicide Attempts ◽  
Case Series ◽  
Population Based ◽  
Additional Increase ◽  
Series Design ◽  
Increased Risk ◽  
Before And After ◽  
Rate Ratios

Abstract Objectives To investigate the association between zolpidem prescription and suicide attempts in people with depression Methods A nationwide, population-based electronic medical records database from the Health Insurance Review & Assessment Service of South was used to investigate the incidence rate ratios (IRRs) of suicide attempts and probable suicide attempts in people with depression before and after zolpidem prescription using self-controlled case series design. Results In a total of 445 people who attempted suicide and 23 141 people who attempted probable suicide attempt, the IRRs of suicidal behavior during the risk periods before and after zolpidem prescription increased compared with those at the baseline. The IRRs gradually increased and peaked immediately before the prescription of zolpidem. The IRR was 70.06 (95% CI: 25.58–191.90) on day 2 before zolpidem prescription and 63.35 (95% CI: 22.99–174.59) on day 1 after zolpidem prescription in the suicide attempt group. The IRR was 24.07 (95% CI: 20.50–28.26) on the day before zolpidem prescription and 14.96 (95% CI: 12.21–18.34) on the day after zolpidem prescription in the probable suicide attempt group. The ratios declined eventually after zolpidem was prescribed. Conclusions Although zolpidem prescription was associated with an increased risk of suicide attempts in people with depression, the risk increased and peaked immediately before zolpidem prescription. The risk declined gradually thereafter. This result indicates that the risk of suicide attempts increases at the time of zolpidem prescription. However, zolpidem prescription does not contribute to additional increase in the risk of suicide attempts.

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