Rehydration after Exercise Dehydration in Heat: Effects of Caffeine Intake

2005 ◽  
Vol 14 (4) ◽  
pp. 294-300 ◽  
Author(s):  
João C. Dias ◽  
Melissa W. Roti ◽  
Amy C. Pumerantz ◽  
Greig Watson ◽  
Daniel A. Judelson ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Urine Osmolality ◽  
Tolerance Test ◽  
Caffeine Intake ◽  
Hydration Status ◽  
Caffeine Ingestion ◽  
College Age ◽  
Heat Effects ◽  
Total Plasma Protein ◽  
Chronic Caffeine

Context:Dieticians, physiologists, athletic trainers, and physicians have recommended refraining from caffeine intake when exercising because of possible fluid-electrolyte imbalances and dehydration.Objective:To assess how 16-hour rehydration is affected by caffeine ingestion.Design:Dose–response.Setting:Environmental chamber.Participants:59 college-age men.Intervention:Subjects consumed a chronic caffeine dose of 0 (placebo), 3, or 6 mg · kg−1· day−1and performed an exercise heat-tolerance test (EHT) consisting of 90 minutes of walking on a treadmill (5.6 km/h) in the heat (37.7 °C).Outcome Measures:Fluid-electrolyte measures.Results:There were no between-group differences immediately after and 16 hours after EHT in total plasma protein, hematocrit, urine osmolality, specific gravity, color, and volume. Body weights after EHT and the following day (16 hours) were not different between groups (P> .05).Conclusion:Hydration status 16 hours after EHT did not change with chronic caffeine ingestion.

scholarly journals Chronic caffeine intake decreases circulating catecholamines and prevents diet-induced insulin resistance and hypertension in rats

2011 ◽  
Vol 107 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Silvia V. Conde ◽  
Tiago Nunes da Silva ◽  
Constancio Gonzalez ◽  
Miguel Mota Carmo ◽  
Emilia C. Monteiro ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Weight Gain ◽  
Visceral Fat ◽  
Tolerance Test ◽  
Caffeine Intake ◽  
Insulin Tolerance ◽  
Hepatic Glutathione ◽  
Chronic Caffeine ◽  
High Sucrose

We tested the hypothesis that long-term caffeine intake prevents the development of insulin resistance and hypertension in two pathological animal models: the high-fat (HF) and the high-sucrose (HSu) diet rat. We used six groups of animals: control; caffeine-treated (Caff; 1 g/l in drinking water during 15 d); HF; caffeine-treated HF (HFCaff); HSu; caffeine-treated HSu (HSuCaff). Insulin sensitivity was assessed using the insulin tolerance test. Blood pressure, weight gain, visceral fat, hepatic glutathione, plasma caffeine, insulin and NO, and serum NEFA and catecholamines were measured. Caffeine reversed insulin resistance and hypertension induced by both the HF and HSu diets. In the HF-fed animals caffeine treatment restored fasting insulin levels to control values and reversed increased weight gain and visceral fat mass. In the HSu group, caffeine reversed fasting hyperglycaemia and restored NEFA to control values. There were no changes either in plasma NO or in hepatic glutathione levels. In contrast, caffeine totally prevented the increase in serum catecholamines induced by HF and HSu diets. To test the hypothesis that inhibition of the sympathetic nervous system prevents the development of diet-induced insulin resistance we administered carvedilol, an antagonist of β1, β2 and also α1 adrenoceptors, to HF and HSu rats. Carvedilol treatment fully prevented diet-induced insulin resistance and hypertension, mimicking the effect of caffeine. We concluded that long-term caffeine intake prevented the development of insulin resistance and hypertension in HF and HSu models and that this effect was related to a decrease in circulating catecholamines.

Hydration Status, Sweat Rates, and Rehydration Education of Youth Football Campers

2009 ◽  
Vol 18 (4) ◽  
pp. 535-552 ◽  
Author(s):  
Brendon P. McDermott ◽  
Douglas J. Casa ◽  
Susan W. Yeargin ◽  
Matthew S. Ganio ◽  
Rebecca M. Lopez ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Field Research ◽  
Urine Osmolality ◽  
Positive Influence ◽  
Hydration Status ◽  
Fluid Consumption ◽  
Subsequent Performance ◽  
Type Design ◽  
Youth Football ◽  
Fluid Losses

Context:Previous field research has not identified sweat rates (SR), fluid consumption (FC), or the efficacy of an educational intervention (EI) for youth during football camp.Objective:To measure hydration status and rehydration performance and examine EI using these data.Design:Observational with EI randomized comparison.Participants:Thirty-three boys (mean ± SD: 12 ± 2 y, 52.9 ± 13.6 kg, 156 ± 12 cm) volunteered during a 5-d camp with 3 (~2-h) sessions per day (WBGT: 25.6 ± 0.5°C).Main Outcome Measures:Hydration status, SR, and FC.Results:Urine osmolality averaged 796 ± 293 mOsm/L for days 2-5. Game SR (1.30 ± 0.57 L/h) was significantly greater than practice SR (0.65 ± 0.35 L/h; P = .002). Subjects dehydrated during free time but matched fluid losses with FC (0.76 ± 0.29 L/h) during football activities.Conclusions:Subjects arrived at camp hypohydrated and maintained this condition. They matched FC and SR during, but dehydrated when not playing, football. This may impair recovery and subsequent performance. Hydration EI seemed to have a positive influence on hydration practices.

Effect of Acute and Chronic Caffeine Use on the Cerebrovascular, Cardiovascular and Hormonal Responses to Orthostasis in Healthy Volunteers

1995 ◽  
Vol 89 (5) ◽  
pp. 475-480 ◽  
Author(s):  
Kwasi Debrah ◽  
Rob Haigh ◽  
Robert Sherwin ◽  
June Murphy ◽  
David Kerr
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Healthy Volunteers ◽  
Peripheral Tolerance ◽  
Caffeine Intake ◽  
Acute Effects ◽  
Caffeine Ingestion ◽  
Hormone Levels ◽  
Chronic Caffeine

1. The effects of acute and chronic caffeine ingestion on supine- and tilt- (60 min at 70°) induced changes in middle cerebral artery velocity (Vmca), heart rate, blood pressure and counter-regulatory hormone levels (catecholamines, growth hormone and cortisol) were studied in nine healthy volunteers. A double-blind, placebo-controlled design was used to study acute effects followed by an open study after 6 days of chronic caffeine use. 2. In the supine position, acute ingestion of caffeine (250 mg) was associated with a fall in Vmca [−11 cm/s, point estimate of difference versus placebo (95% confidence interval: −17, −6) cm/s, P < 0.001] and a rise in mean arterial pressure [+4 (1, 6) mmHg, P < 0.01] and plasma adrenaline levels [+138 (53, 223) pmol/l, P < 0.01]. After chronic caffeine use, the pressor and adrenaline responses, but not the drop in Vmca, were significantly attenuated. 3. On tilting to 70° the fall in Vmca was greater with placebo than after acute caffeine ingestion [−10 (−14, −15) cm/s, P < 0.01], whereas increments (above supine values) in heart rate, mean arterial pressure and hormone levels were unchanged by caffeine. In contrast, the adrenaline [+126 (29, 282) pmol/l, P < 0.01] and noradrenaline [+ 0.6 (0.1, 0.9) nmol/l, P < 0.05] responses to tilting were augmented after acute caffeine ingestion. Chronic caffeine supplementation did not alter the fall in Vmca associated with tilting, but significantly attenuated the adrenaline response (P < 0.01 compared with the acute study). 4. Acute caffeine ingestion and orthostasis are both associated with a reduction in Vmca and a rise in mean arterial pressure and adrenaline levels. The acute effects of caffeine on mean arterial pressure and adrenaline but not on Vmca are lost with sustained caffeine intake. These results suggest dissociation between the development of central and peripheral tolerance after chronic caffeine use.

scholarly journals Caffeine Supplementation for Powerlifting Competitions: an Evidence-Based Approach

2019 ◽  
Vol 68 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Jozo Grgic ◽  
Filip Sabol ◽  
Sandro Venier ◽  
Jason Tallis ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Bench Press ◽  
Caffeine Intake ◽  
Evidence Based ◽  
Negative Effects ◽  
Caffeine Consumption ◽  
Caffeine Ingestion ◽  
Repetition Maximum ◽  
Rest Periods ◽  
Chronic Caffeine ◽  
Repeated Dosing

AbstractIn this paper, we review the effects of caffeine on muscle strength and provide suggestions for caffeine supplementation in powerlifting competitions. The currently available studies indicate that caffeine ingestion may enhance strength in two powerlifting competition events, the squat and the bench press. For the deadlift, the same might be expected even though studies directly using this event are lacking. Optimal doses of caffeine are likely in the range from 2 to 6 mg·kg−1, and are highly individual. When using caffeine-containing capsules, 60 minutes pre-exercise seems to be a good timing of caffeine consumption. For other sources such as caffeinated chewing gum, a shorter period (5 to 10 min) from consumption to the start of the exercise seems to be effective. For shorter duration powerlifting competitions (e.g., 2 hours), one pre-competition dose of caffeine could be sufficient for acute performance-enhancing effects that might be maintained across all three events. For longer duration competitions (with longer rest periods between one repetition maximum attempts), there might be a benefit to repeated dosing with caffeine; for example, ingesting smaller doses of caffeine before each attempt or event. During training, powerlifters may consider ingesting caffeine only before the training sessions with the highest intensity. This approach might eliminate the attenuation of caffeine’s effects associated with chronic caffeine ingestion and would help in maximizing performance benefits from acute caffeine ingestion at the competition. Nonetheless, withdrawal from caffeine (e.g., no caffeine intake seven days before competition) does not seem necessary and may have some indirect negative effects.

Effects of Chronic Caffeine Ingestion on Growth and Myocardial Function

1985 ◽  
Vol 179 (3) ◽  
pp. 388-395 ◽  
Author(s):  
T. E. Temples ◽  
D. J. Geoffray ◽  
T. Nakamoto ◽  
A. D. Hartman ◽  
H. I. Miller
Keyword(s):  
Myocardial Function ◽  
Caffeine Ingestion ◽  
Chronic Caffeine

scholarly journals Availability of a Flavored Beverage and Impact on Children’s Hydration Status, Sleep, and Mood

Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1757
Author(s):  
Michael R. Szymanski ◽  
Gabrielle E. W. Giersch ◽  
Margaret C. Morrissey ◽  
Courteney L. Benjamin ◽  
Yasuki Sekiguchi ◽  
...  
Keyword(s):  
Sleep Quality ◽  
Quality Index ◽  
Pittsburgh Sleep Quality Index ◽  
Intervention Group ◽  
Urine Osmolality ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Control Group ◽  
Profile Of Mood States ◽  
Urine Color

Euhydration remains a challenge in children due to lack of access and unpalatability of water and to other reasons. The purpose of this study was to determine if the availability/access to a beverage (Creative Roots®) influences hydration in children and, therefore, sleep quality and mood. Using a crossover investigation, 46 participants were randomly assigned to a control group (CON) or an intervention group and received Creative Roots® (INT) for two-week periods. We recorded daily first morning and afternoon urine color (Ucol), thirst perception, and bodyweight of the two groups. Participants reported to the lab once per week and provided first morning urine samples to assess Ucol, urine specific gravity (USG), and urine osmolality (Uosmo). Participants also completed the questionnaires Profile of Mood States-Adolescents (POMS-a) and Pittsburgh Sleep Quality Index (PSQI). Dependent t-tests were used to assess the effects of the intervention on hydration, mood, and sleep quality. Uosmo was greater and Ucol was darker in the control group (mean ± SD) [Uosmo: INT = 828 ± 177 mOsm·kg−1, CON = 879 ± 184 mOsm·kg−1, (p = 0.037], [Ucol:INT = 5 ± 1, CON = 5 ± 1, p = 0.024]. USG, POMS-a, and PSQI were not significant between the groups. At-home daily afternoon Ucol was darker in the control group [INT = 3 ± 1, CON = 3 ± 1, p = 0.022]. Access to Creative Roots® provides a small, potentially meaningful hydration benefit in children. However, children still demonstrated consistent mild dehydration based on Uosmo, despite consuming the beverage.

Caffeine-Induced Psychosis

CNS Spectrums ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 127-131 ◽  
Author(s):  
Dawson W. Hedges ◽  
Fu Lye Woon ◽  
Scott P. Hoopes
Keyword(s):  
Antipsychotic Medication ◽  
Healthy People ◽  
Caffeine Intake ◽  
Adenosine Antagonist ◽  
Dopamine Transmission ◽  
Chronic Caffeine ◽  
Chronic Psychosis

ABSTRACTAs a competitive adenosine antagonist, caffeine affects dopamine transmission and has been reported to worsen psychosis in people with schizophrenia and to cause psychosis in otherwise healthy people. We report of case of apparent chronic caffeine-induced psychosis characterized by delusions and paranoia in a 47-year-old man with high caffeine intake. The psychosis resolved within 7 weeks after lowering caffeine intake without use of antipsychotic medication. Clinicians might consider the possibility of caffeinism when evaluating chronic psychosis.

Caffeine intake reduces incident atrial fibrillation at a population level

2018 ◽  
Vol 25 (10) ◽  
pp. 1055-1062 ◽  
Author(s):  
Edoardo Casiglia ◽  
Valérie Tikhonoff ◽  
Federica Albertini ◽  
Federica Gasparotti ◽  
Alberto Mazza ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
General Population ◽  
Univariate Analysis ◽  
Population Level ◽  
Caffeine Intake ◽  
General Belief ◽  
The Third ◽  
Chronic Caffeine ◽  
Artery Disease ◽  
Cox Analysis

Background The general belief is that caffeine increases the risk of hyperkinetic arrhythmias, including atrial fibrillation. The aim of this study is to investigate the effect of chronic caffeine intake on incident atrial fibrillation in general population. Design and methods A population cohort of 1475 unselected men and women observed for 12 years and left free to intake food or beverages containing caffeine was studied. Subjects were stratified into tertiles of caffeine intake both in the whole cohort and after genotyping for the –163C > A polymorphism of the CYP1A2 gene, regulating caffeine metabolism. Results In the whole cohort, the 12-year incidence of atrial fibrillation was significantly lower in the third (2.2%) than in the first (10.2%) or second (5.7%) tertile of caffeine intake ( P < 0.001). The same trend was observed in all genotypes; the apparently steeper reduction of atrial fibrillation in slow caffeine metabolisers found at univariate analysis was proved wrong by multivariate Cox analysis. Age, chronic pulmonary disease, history of heart failure and of coronary artery disease, and systolic blood pressure − but not the genotype or the caffeine ×  CYP1A2 interaction term − were significant confounders of the association between incident atrial fibrillation and being in the third tertile of caffeine intake (hazard ratio 0.249, 95% confidence intervals 0.161–0.458, P < 0.01). Conclusions A higher caffeine intake (>165 mmol/day or > 320 mg/day) is associated with a lower incidence of atrial fibrillation in the 12-year epidemiological prospective setting based on the general population.

Effect of Caffeine on Leg-Muscle Pain during Intense Cycling Exercise: Possible Role of Anxiety Sensitivity

2008 ◽  
Vol 18 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Rachael C. Gliottoni ◽  
Robert W. Motl
Keyword(s):  
Pain Intensity ◽  
Anxiety Sensitivity ◽  
High Intensity ◽  
Muscle Pain ◽  
Caffeine Ingestion ◽  
Cycling Exercise ◽  
College Age ◽  
Peak Aerobic Capacity ◽  
Leg Muscle

This experiment examined the effect of a moderate dose of caffeine on perceptions of leg-muscle pain during a bout of high-intensity cycling exercise and the role of anxiety sensitivity in the hypoalgesic effect of caffeine on muscle pain during exercise. Sixteen college-age women ingested caffeine (5 mg/kg body weight) or a placebo and 1 hr later completed 30 min of cycling on an ergometer at 80% of peak aerobic capacity. The conditions were completed in a counterbalanced order, and perceptions of leg-muscle pain were recorded during the bouts of exercise. Caffeine resulted in a large reduction in leg-muscle pain-intensity ratings compared with placebo (d = −0.95), and the reduction in leg-muscle pain-intensity ratings was larger in those with lower anxiety-sensitivity scores than those with higher anxiety-sensitivity scores (d = −1.28 based on a difference in difference scores). The results support that caffeine ingestion has a large effect on reducing leg-muscle pain during high-intensity exercise, and the effect is moderated by anxiety sensitivity.

scholarly journals Effects of the Amount and Frequency of Fluid Intake on Cognitive Performance and Mood among Young Adults in Baoding, Hebei, China: A Randomized Controlled Trial

2020 ◽  
Vol 17 (23) ◽  
pp. 8813
Author(s):  
Hairong He ◽  
Jianfen Zhang ◽  
Na Zhang ◽  
Songming Du ◽  
Shufang Liu ◽  
...  
Keyword(s):  
Randomized Controlled Trial ◽  
Young Adults ◽  
Cognitive Performance ◽  
Fluid Intake ◽  
Controlled Trial ◽  
Urine Osmolality ◽  
Memory Test ◽  
Hydration Status ◽  
Randomized Controlled ◽  
Time Point

Water is a critical nutrient that is important for the maintenance of the physiological function of the human body. This article aimed to investigate the effects of the amount and frequency of fluid intake on cognitive performance and mood. A double-blinded randomized controlled trial was designed and implemented on college students aged 18–23 years in Baoding, China. Participants were randomly assigned into one of three groups: the recommended behavior group (RB group) who drank 200 mL of water every 2 h, the half amount group (HA group) who drank 100 mL of water every 2 h, and the high frequency group (HF group) who drank 110 mL of water every 1 h. The intervention lasted 2 days. Urine osmolality, cognitive performance, and mood of participants in each group were compared using the one-way analysis of variance (ANOVA). A total of 92 participants (46 females, 46 males) completed this study with a completion rate of 95.8%. The urine osmolality of the HA group was higher than that of the RB group and the HF group at two time points (p < 0.05). At time point 1, the scores in the portrait memory test and vigor were statistically different (F = 20.45, p < 0.001; F = 5.46, p = 0.006). It was found that the scores for the portrait memory test in the RB group were lower than those in the HA group and the HF group (p = 0.007; p < 0.001), while the scores of the HF group were higher than those of the HA group (p < 0.001). The scores for vigor in the RB group were significantly higher than those of the HA group (p = 0.006), and they were also significantly higher than those of the HF group (p = 0.004). At time point 2, only the scores for vigor were statistically different (F = 3.80, p = 0.026). It was found that the scores for vigor in the RB group were higher than those in the HA group and HF group (p = 0.018; p = 0.019). Both the amount and frequency of fluid intake may affect urine osmolality and vigor, but these factors have limited impacts on cognitive performance. Rational fluid intake behavior may be beneficial to improve the hydration status and mood of young adults. More research is needed, especially experimental research, to allow causal conclusions to be drawn.

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