scholarly journals How much water is in a mouthful, and how many mouthfuls should I drink? A laboratory exercise to help students understand developing a hydration plan

2021 ◽  
Vol 45 (3) ◽  
pp. 589-593
Author(s):  
Gregory A. Brown ◽  
Brandon S. Shaw ◽  
Ina Shaw

Preventing impairments in athletic performance is an important concept for students that are preparing for careers that involve working with athletes. Gaining hands on, laboratory-based experience in measuring exercise induced dehydration can help students understand how to help athletes prevent dehydration induced impairment in performance. This article describes a laboratory exercise for junior and senior students in a sports nutrition class, in which the students measure changes in body mass (as a measure of dehydration) due to 40 min of moderate-intensity exercise and 40 min of vigorous-intensity exercise. The students also measure how much water is in a mouthful from a sports bottle and from a drinking fountain. The students then calculate how many mouthfuls are necessary to replace exercise induced fluid losses. This laboratory exercise has been well received by students and has improved performance on the test regarding hydration.

2019 ◽  
Vol 30 (2) ◽  
pp. 525-533 ◽  
Author(s):  
J J Steventon ◽  
C Foster ◽  
H Furby ◽  
D Helme ◽  
R G Wise ◽  
...  

Abstract Long-term exercise interventions have been shown to be a potent trigger for both neurogenesis and vascular plasticity. However, little is known about the underlying temporal dynamics and specifically when exercise-induced vascular adaptations first occur, which is vital for therapeutic applications. In this study, we investigated whether a single session of moderate-intensity exercise was sufficient to induce changes in the cerebral vasculature. We employed arterial spin labeling magnetic resonance imaging to measure global and regional cerebral blood flow (CBF) before and after 20 min of cycling. The blood vessels’ ability to dilate, measured by cerebrovascular reactivity (CVR) to CO2 inhalation, was measured at baseline and 25-min postexercise. Our data showed that CBF was selectively increased by 10–12% in the hippocampus 15, 40, and 60 min after exercise cessation, whereas CVR to CO2 was unchanged in all regions. The absence of a corresponding change in hippocampal CVR suggests that the immediate and transient hippocampal adaptations observed after exercise are not driven by a mechanical vascular change and more likely represents an adaptive metabolic change, providing a framework for exploring the therapeutic potential of exercise-induced plasticity (neural, vascular, or both) in clinical and aged populations.


2010 ◽  
Vol 103 (10) ◽  
pp. 1480-1484 ◽  
Author(s):  
Narelle M. Berry ◽  
Kade Davison ◽  
Alison M. Coates ◽  
Jonathan D. Buckley ◽  
Peter R. C. Howe

Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure (BP) responses to exercise in individuals who are overweight/obese. The present study investigated whether consumption of cocoa flavanols, which improve endothelium-dependent flow-mediated dilatation (FMD), can modify BP responsiveness to exercise. Twenty-one volunteers (eight females and thirteen males, 54·9 (se2·2) years, BMI 31·6 (se0·8) kg/m2, systolic BP 134 (se2) mmHg, diastolic BP (DBP) 87 (se2) mmHg) were randomised to consume single servings of either a high-flavanol (HF, 701 mg) or a low-flavanol (LF, 22 mg) cocoa beverage in a double-blind, cross-over design with 3–7-d washout between treatments. Two hours after cocoa consumption, FMD was measured, followed by continuous beat-to-beat assessment (Finapres™) of BP before and during 10 min of cycling at 75 % of age-predicted maximum heart rate. Averaged data from two assessments on each type of beverage were compared by analysis of covariance using pre-exercise BP as the covariate. Pre-exercise BP was similar after taking LF and HF (153 (se3)/88 (se3)v. 153 (se4)/87 (se2) mmHg, respectively,P>0·05). However, the BP response to exercise (area under BP curve) was attenuated by HF compared with LF. BP increases were 68 % lower for DBP (P = 0·03) and 14 % lower for mean BP (P = 0·05). FMD measurements were higher after taking HF than after taking LF (6·1 (se0·6) %v. 3·4 (se0·5) %,P < 0·001). By facilitating vasodilation and attenuating exercise-induced increases in BP, cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals.


2015 ◽  
Vol 12 (6) ◽  
pp. 770-775 ◽  
Author(s):  
Yan Wang ◽  
Lea A. Cupul-Uicab ◽  
Walter J. Rogan ◽  
Merete Eggesbo ◽  
Gregory Travlos ◽  
...  

Background:Pregnant women who are physically active have a lower risk of preeclampsia and gestational diabetes than women who are less active. One possible mechanism is a reduction in low-grade inflammation, as measured by plasma concentrations of C-reactive protein (CRP). The association between exercise and CRP in pregnant women, however, has not been adequately investigated.Methods:A total of 537 pregnant women, enrolled around the 17th week of gestation in the Norwegian Mother and Child Cohort Study in 2003 to 2004, were studied. Self-reported recreational exercise was recalled for both 3 months before pregnancy and early pregnancy. The total energy expenditure from recreational exercise (total recreational exercise, metabolic equivalent of task [MET]-hr/week) was estimated, and low-, moderate- and vigorous-intensity exercise was defined. Plasma CRP concentrations were measured during pregnancy.Results:In adjusted linear regression models, mean CRP concentration was 1.0% lower [95% CI = –1.9% to 0.2%] with each 1 MET-hr/week of total recreational exercise before pregnancy. In addition, vigorous-intensity exercise before pregnancy was more strongly related to a reduction in CRP levels than low- or moderate-intensity exercise. However, we observed no association between recreational exercise during pregnancy and plasma CRP levels.Conclusion:Recreational exercise before pregnancy, especially vigorous exercise, may reduce the risk of maternal inflammation during pregnancy.


2016 ◽  
Vol 38 (4) ◽  
pp. 396-408 ◽  
Author(s):  
Christopher J. Brush ◽  
Ryan L. Olson ◽  
Peter J. Ehmann ◽  
Steven Osovsky ◽  
Brandon L. Alderman

The purpose of this study was to examine possible dose–response and time course effects of an acute bout of resistance exercise on the core executive functions of inhibition, working memory, and cognitive flexibility. Twenty-eight participants (14 female; Mage = 20.5 ± 2.1 years) completed a control condition and resistance exercise bouts performed at 40%, 70%, and 100% of their individual 10-repetition maximum. An executive function test battery was administered at 15 min and 180 min postexercise to assess immediate and delayed effects of exercise on executive functioning. At 15 min postexercise, high-intensity exercise resulted in less interference and improved reaction time (RT) for the Stroop task, while at 180 min low- and moderate-intensity exercise resulted in improved performance on plus–minus and Simon tasks, respectively. These findings suggest a limited and task-specific influence of acute resistance exercise on executive function in healthy young adults.


2010 ◽  
Vol 108 (4) ◽  
pp. 769-779 ◽  
Author(s):  
Dylan Thompson ◽  
Daniella Markovitch ◽  
James A. Betts ◽  
Dawn Mazzatti ◽  
James Turner ◽  
...  

Regular exercise may improve systemic markers of chronic inflammation, but direct evidence and dose-response information is lacking. The objective of this study was to examine the effect and time course of changes in markers of chronic inflammation in response to progressive exercise training (and subsequent detraining). Forty-one sedentary men 45–64 yr of age completed either a progressive 24-wk exercise intervention or control followed by short-term removal of the intervention (2-wk detraining). Serum IL-6 fell by −0.4 pg/ml (SD 0.6) after 12 wk and responded to moderate-intensity exercise. Serum alanine aminotransferase (ALT) activity fell −7 U/l (SD 11) at 24 wk although there was no evidence of any change by week 12 (and therefore ALT required more vigorous-intensity activity and/or a more prolonged intervention). The effect on IL-6 was lost after 2-wk detraining whereas the change in ALT was retained. The temporal fall and rise in IL-6 with training and subsequent detraining in men with high IL-6 at baseline provided a retrospective opportunity to examine parallel genomic changes in peripheral mononuclear cells. A subset of 53 probes was differentially regulated by at least twofold after training with 31 of these changes being lost after detraining ( n = 6). IL-6 responded quickly to the carefully monitored exercise intervention (within weeks) and required only moderate-intensity exercise, whereas ALT took longer to change and/or required more vigorous-intensity exercise. Further work is required to determine whether any of the genes that temporally changed in parallel with changes in IL-6 are a cause or consequence of this response.


2015 ◽  
Vol 4 (1) ◽  
pp. 118-125
Author(s):  
Jeffrey A. Woods ◽  
Brandt D. Pence

Exercise immunology is a relatively new discipline in the exercise sciences that seeks to understand how exercise affects the immune system and susceptibility to infectious and chronic diseases. This brief review will focus on three major observations that have driven the field to date including: (1) acute exercise-induced leukocytosis, (2) the observation that intense, prolonged exercise results in upper respiratory tract symptoms, and (3) the paradoxical effect of acute and chronic exercise on inflammation. This framework will be used to examine the mechanisms and implications behind these seminal observations. Data generally support the conclusion that moderate intensity exercise enhances immune function, whereas prolonged, intense exercise diminishes immune function.


2007 ◽  
Vol 103 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Alastair N. H. Hodges ◽  
A. William Sheel ◽  
John R. Mayo ◽  
Donald C. McKenzie

The purpose of this study was to examine the effects of exercise on extravascular lung water as it may relate to pulmonary gas exchange. Ten male humans underwent measures of maximal oxygen uptake (V̇o2 max) in two conditions: normoxia (N) and normobaric hypoxia of 15% O2 (H). Lung density was measured by quantified MRI before and 48.0 ± 7.4 and 100.7 ± 15.1 min following 60 min of cycling exercise in N (intensity = 61.6 ± 9.5% V̇o2 max) and 55.5 ± 9.8 and 104.3 ± 9.1 min following 60 min cycling exercise in H (intensity = 65.4 ± 7.1% hypoxic V̇o2 max), where V̇o2 max = 65.0 ± 7.5 ml·kg−1·min−1 (N) and 54.1 ± 7.0 ml·kg−1·min−1 (H). Two subjects demonstrated mild exercise-induced arterial hypoxemia (EIAH) [minimum arterial oxygen saturation (SaO2 min) = 94.5% and 93.8%], and seven subjects demonstrated moderate EIAH (SaO2 min = 91.4 ± 1.1%) as measured noninvasively during the V̇o2 max test in N. Mean lung densities, measured once preexercise and twice postexercise, were 0.177 ± 0.019, 0.181 ± 0.019, and 0.173 ± 0.019 g/ml (N) and 0.178 ± 0.021, 0.174 ± 0.022, and 0.176 ± 0.019 g/ml (H), respectively. No significant differences ( P > 0.05) were found in lung density following exercise in either condition or between conditions. Transient interstitial pulmonary edema did not occur following sustained steady-state cycling exercise in N or H, indicating that transient edema does not result from pulmonary capillary leakage during sustained submaximal exercise.


2019 ◽  
Vol 9 (22) ◽  
pp. 4827 ◽  
Author(s):  
Joames K. Freitas Leal ◽  
Dan Lazari ◽  
Coen C.W.G. Bongers ◽  
Maria T.E. Hopman ◽  
Roland Brock ◽  
...  

Our knowledge on the molecular mechanisms of red blood cell aging is mostly derived from in vitro studies. The Four Days Marches of Nijmegen in the Netherlands, the world’s largest yearly walking event, constitutes a unique possibility to study the effect of mechanical and biochemical stressors occurring during moderate-intensity exercise on red blood cell aging in vivo. Therefore, longitudinal measurements were performed of biophysical, immunological, and functional red blood cell characteristics that are known to change during aging. Our data show that moderate-intensity exercise induces the generation of a functionally improved red blood cell population with a higher deformability and a decreased tendency to aggregate. This is likely to be associated with an early removal of the oldest red blood cells from the circulation, as deduced from the (dis)appearance of removal signals. Thus, the physiological red blood cell aging process maintains homeostasis in times of moderate-intensity exercise-induced stress, probably by accelerated aging and subsequent removal of the oldest, most vulnerable red blood cells.


2015 ◽  
Vol 27 (2) ◽  
pp. 192-202 ◽  
Author(s):  
Alice Emily Thackray ◽  
Laura Ann Barrett ◽  
Keith Tolfrey

Eleven healthy girls (mean ± SD: age 12.1 ± 0.6 years) completed three 2-day conditions in a counterbalanced, crossover design. On day 1, participants either walked at 60 (2)% peak oxygen uptake (energy deficit 1.55[0.20] MJ), restricted food energy intake (energy deficit 1.51[0.25] MJ) or rested. On day 2, capillary blood samples were taken at predetermined intervals throughout the 6.5 hr postprandial period before, and following, the ingestion of standardized breakfast and lunch meals. Fasting plasma triacylglycerol concentrations (TAG) was 29% and 13% lower than rest control in moderate-intensity exercise (effect size [ES] = 1.39, p = .01) and energy-intake restriction (ES = 0.57, p = .02) respectively; moderate-intensity exercise was 19% lower than energy-intake restriction (ES = 0.82, p = .06). The moderate-intensity exercise total area under the TAG versus time curve was 21% and 13% lower than rest control (ES = 0.71, p = .004) and energy-intake restriction (ES = 0.39, p = .06) respectively; energy-intake restriction was marginally lower than rest control (-10%; ES = 0.32, p = .12). An exercise-induced energy deficit elicited a greater reduction in fasting plasma TAG with a trend for a larger attenuation in postprandial plasma TAG than an isoenergetic diet-induced energy deficit in healthy girls.


2008 ◽  
Vol 100 (5) ◽  
pp. 1109-1115 ◽  
Author(s):  
Stephen Whybrow ◽  
Darren A. Hughes ◽  
Patrick Ritz ◽  
Alexandra M. Johnstone ◽  
Graham W. Horgan ◽  
...  

The effects of incremental exercise on appetite, energy intake (EI), expenditure (EE) and balance (EB) in lean men and women were examined. Six men (age 29·7 (sd5·9) years, weight 75·2 (sd15·3) kg, height 1·75 (sd0·11) m) and six women (age 24·7 (sd5·9) years, weight 66·7 (sd9·10) kg, height 1·70 (sd0·09) m) were each studied three times during a 16 d protocol, corresponding to no additional exercise (Nex), moderate-intensity exercise (Mex; 1·5–2·0 MJ/d) and high-intensity exercise (Hex; 3·0–4·0 MJ/d) regimens. Subjects were fed to EB during days 1–2, and during days 3–16 they fedad libitumfrom a medium-fat diet of constant composition. Daily EE, assessed using the doubly labelled water method, was 9·2, 11·6 and 13·7 MJ/d (P < 0·001;sed0·45) for the women and 12·2, 14·0 and 16·7 MJ/d (P = 0·007;sed1·11) for the men on the Nex, Mex and Hex treatments, respectively. EI was 8·3, 8·6 and 9·9 MJ/d (P = 0·118;sed0·72) for the women and 10·6, 11·6 and 12·0 MJ/d (P = 0·031;sed0·47) for the men, respectively. On average, subjects compensated for about 30 % of the exercise-induced energy deficit. However, the degree of compensation varied considerably among individuals. The present study captured the initial compensation in EI for exercise-induced energy deficits. Total compensation would take a matter of weeks.


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