Effects of acute caffeine withdrawal on habituated male runners

1994 ◽  
Vol 76 (3) ◽  
pp. 1043-1048 ◽  
Author(s):  
R. K. Hetzler ◽  
N. Warhaftig-Glynn ◽  
D. L. Thompson ◽  
E. Dowling ◽  
A. Weltman
Keyword(s):  
Repeated Measures ◽  
Lactate Threshold ◽  
Substrate Utilization ◽  
Caffeine Intake ◽  
Loading Dose ◽  
Testing Session ◽  
O2 Uptake ◽  
Double Blind ◽  
Caffeine Withdrawal ◽  
Double Blind Design

This study investigated the effects of caffeine withdrawal on six trained caffeine-habituated male runners: age 29.8 +/- 5.8 (SD) yr, height 180.4 +/- 5.4 cm, weight 77.3 +/- 6.7 kg, maximal O2 uptake 63.0 +/- 5.4 ml.kg-1.min-1, and daily caffeine intake 674 +/- 128 mg. The subjects received a loading dose (5 mg/kg body wt) of caffeine 48 h before each testing session. They were then given (using a repeated-measures double-blind design) additional doses of caffeine (5 mg/kg body wt) or a placebo 36, 24, 12, and 2 h before testing. They ran at a velocity corresponding to their lactate threshold for 60 min in a caffeine withdrawal or caffeinated condition. Caffeine withdrawal resulted in no significant differences in absolute O2 uptake, O2 uptake relative to maximal O2 uptake, respiratory exchange ratios, or free fatty acid concentrations. Glycerol concentrations were significantly attenuated in the withdrawal condition. No significant differences were revealed in calculated substrate utilization. It was concluded that caffeine withdrawal significantly affects lipolysis but not substrate utilization during prolonged running.

The effect of intermittent hypobaric hypoxic exposure and sea level training on submaximal economy in well-trained swimmers and runners

2008 ◽  
Vol 104 (2) ◽  
pp. 328-337 ◽  
Author(s):  
Martin J. Truijens ◽  
Ferran A. Rodríguez ◽  
Nathan E. Townsend ◽  
James Stray-Gundersen ◽  
Christopher J. Gore ◽  
...  
Keyword(s):  
Sea Level ◽  
Repeated Measures ◽  
Hypobaric Hypoxia ◽  
Lactate Concentration ◽  
Hypoxic Exposure ◽  
Double Blind ◽  
Intermittent Hypobaric Hypoxia ◽  
Post Test ◽  
Double Blind Design ◽  
Level Training

To evaluate the effect of intermittent hypobaric hypoxia combined with sea level training on exercise economy, 23 well-trained athletes (13 swimmers, 10 runners) were assigned to either hypobaric hypoxia (simulated altitude of 4,000–5,500 m) or normobaric normoxia (0–500 m) in a randomized, double-blind design. Both groups rested in a hypobaric chamber 3 h/day, 5 days/wk for 4 wk. Submaximal economy was measured twice before (Pre) and after (Post) the treatment period using sport-specific protocols. Economy was estimated both from the relationship between oxygen uptake (V̇o2) and speed, and from the absolute V̇o2 at each speed using sport-specific protocols. V̇o2 was measured during the last 60 s of each (3–4 min) stage using Douglas bags. Ventilation (V̇e), heart rate (HR), and capillary lactate concentration ([La−]) were measured during each stage. Velocity at maximal V̇o2 (velocity at v̇o2max) was used as a functional indicator of changes in economy. The average V̇o2 for a given speed of the Pre values was used for Post test comparison using a two-way, repeated-measures ANOVA. Typical error of measurement of V̇o2 was 4.7% (95% confidence limits 3.6–7.1), 3.6% (2.8–5.4), and 4.2% (3.2–6.9) for speeds 1, 2, and 3, respectively. There was no change in economy within or between groups (ANOVA interaction P = 0.28, P = 0.23, and P = 0.93 for speeds 1, 2, and 3). No differences in submaximal HR, [La−], V̇e, or velocity at V̇o2max were found between groups. It is concluded that 4 wk of intermittent hypobaric hypoxia did not improve submaximal economy in this group of well-trained athletes.

Six weeks of oral Echinacea purpurea supplementation does not enhance the production of serum erythropoietin or erythropoietic status in recreationally active males with above-average aerobic fitness

2019 ◽  
Vol 44 (7) ◽  
pp. 791-795
Author(s):  
Tyler D. Martin ◽  
Michael S. Green ◽  
Malcolm T. Whitehead ◽  
Timothy P. Scheett ◽  
Michael J. Webster ◽  
...  
Keyword(s):  
Aerobic Fitness ◽  
Repeated Measures ◽  
Hemoglobin Concentration ◽  
Echinacea Purpurea ◽  
Matched Pair ◽  
Mean Corpuscular Hemoglobin ◽  
Double Blind ◽  
Factorial Anova ◽  
Double Blind Design ◽  
Serum Erythropoietin

The purpose of this study was to investigate the effect of 6 weeks of oral Echinacea purpurea supplementation on serum erythropoietin (EPO) and erythropoietic status. Twenty-four males (mean ± SE; age = 25.2 ± 1.4 years, height = 178.1 ± 1.4 cm, body mass = 78.1 ± 1.6 kg, body fat = 12.7 ± 0.9%, maximal oxygen uptake = 52.9 ± 0.9 mL·kg−1·min−1) were randomly grouped using a matched-pair, double-blind design and self-administered 8000 mg·day−1 of either E. purpurea (n = 12) or placebo (n = 12) for 42 consecutive days. Blood samples were collected prior to supplementation (day 0) and every 2 weeks during the supplementation period (days 14, 28, and 42) and were analyzed for EPO, red blood cell count, hemoglobin concentration, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin concentration. Separate 2 × 4 (group × time) factorial ANOVA with repeated measures on time were used to determine statistical differences with significance set at p ≤ 0.05. There were no significant interaction, group, or time effects observed for EPO or erythropoietic status markers for any of the measurement points (p ≤ 0.05). The present study indicated that 6 weeks of oral E. purpurea supplementation in recreationally active males with above average aerobic fitness did not enhance EPO or erythropoietic status. These findings are in contrast with previous reports of E. purpurea supplementation in untrained participants with average fitness levels, but consistent with observations in trained endurance athletes.

scholarly journals The Effects of High Doses of Caffeine on Maximal Strength and Muscular Endurance in Athletes Habituated to Caffeine

Nutrients ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1912 ◽  
Author(s):  
Michal Wilk ◽  
Michal Krzysztofik ◽  
Aleksandra Filip ◽  
Adam Zajac ◽  
Juan Del Coso
Keyword(s):  
Body Mass ◽  
Repeated Measures ◽  
Bench Press ◽  
Muscle Endurance ◽  
Experimental Session ◽  
Maximal Strength ◽  
Double Blind ◽  
Significant Difference ◽  
Endurance Tests ◽  
Double Blind Design

Background: The main goal of this study was to assess the acute effects of the intake of 9 and 11 mg/kg/ body mass (b.m.) of caffeine (CAF) on maximal strength and muscle endurance in athletes habituated to caffeine. Methods: The study included 16 healthy strength-trained male athletes (age = 24.2 ± 4.2 years, body mass = 79.5 ± 8.5 kg, body mass index (BMI) = 24.5 ± 1.9, bench press 1RM = 118.3 ± 14.5 kg). All participants were habitual caffeine consumers (4.9 ± 1.1 mg/kg/b.m., 411 ± 136 mg of caffeine per day). This study had a randomized, crossover, double-blind design, where each participant performed three experimental sessions after ingesting either a placebo (PLAC) or 9 mg/kg/b.m. (CAF-9) and 11 mg/kg/b.m. (CAF-11) of caffeine. In each experimental session, participants underwent a 1RM strength test and a muscle endurance test in the bench press exercise at 50% 1RM while power output and bar velocity were measured in each test. Results: A one-way repeated measures ANOVA revealed a significant difference between PLAC, CAF-9, and CAF-11 groups in peak velocity (PV) (p = 0.04). Post-hoc tests showed a significant decrease for PV (p = 0.04) in the CAF-11 compared to the PLAC group. No other changes were found in the 1RM or muscle endurance tests with the ingestion of caffeine. Conclusion: The results of the present study indicate that high acute doses of CAF (9 and 11 mg/kg/b.m.) did not improve muscle strength nor muscle endurance in athletes habituated to this substance.

Effects of Chromium Picolinate Supplementation on Body Composition, Strength, and Urinary Chromium Loss in Football Players

1994 ◽  
Vol 4 (2) ◽  
pp. 142-153 ◽  
Author(s):  
Stephan P. Clancy ◽  
Priscilla M. Clarkson ◽  
Michael E. DeCheke ◽  
Kazunori Nosaka ◽  
Patty S. Freedson ◽  
...  
Keyword(s):  
Body Composition ◽  
Repeated Measures ◽  
Dynamic Strength ◽  
Weight Lifting ◽  
Chromium Picolinate ◽  
Football Players ◽  
Double Blind ◽  
Significant Group ◽  
Double Blind Design ◽  
Urinary Chromium

The effects of 9 weeks of daily chromium supplementation (200μg Cr as picolinate) were investigated in a double-blind design in football players during spring training. Testing was done pre-, mid-, and postsupplementation on the following criterion measures: urinary chromium excretion, girth and skinfold measures, percent body fat and lean body mass, and isometric and dynamic strength. With the exception of 2 variables (of 65 variables analyzed), no significant group by trials interactions were found (based on a repeated measures ANOVA). The two exceptions were unrelated and inconsequential. For 27 of the 38 subjects, average urinary chromium loss at pre was 0.36 μg/24 hr, whereas it was undetectable (< 0.1 μg/24 hr) for 10 subjects and excessive in 1 subject (2.4 μg/24 hr). Subjects receiving chromium supplements demonstrated urinary chromium losses five times greater than those in the placebo group at mid and post. Chromium picolinate supplementation was ineffective in bringing about changes in body composition or strength during a program of intensive weight-lifting training.

Influence of Caffeine on Metabolic and Cardiovascular Functions during Sustained Light Intensity Cycling and at Rest

1999 ◽  
Vol 9 (4) ◽  
pp. 361-370 ◽  
Author(s):  
Hermann-J. Engels ◽  
John C. Wirth ◽  
Sueda Celik ◽  
Jodee L. Dorsey
Keyword(s):  
Blood Pressure ◽  
Light Intensity ◽  
Arterial Blood Pressure ◽  
Repeated Measures ◽  
Dosage Level ◽  
Open Circuit ◽  
Caffeine Intake ◽  
Double Blind ◽  
Arterial Blood ◽  
Cardiovascular Functions

This study assessed the influence of caffeine on metabolic and cardiovascular functions during sustained, light intensity cycling and at rest. Eight healthy, recreationally active adults participated in four randomly assigned, double-blind experimental trials of 60 min upright seated cycle exercise (30% VO2max) or equivalent rest with caffeine (5 mg ⋅ kg−1) or placebo consumed 60 min prior to data collection. Gas exchange was measured by open-circuit spirom-etry indirect calorimetry. Global blood flow was evaluated by thoracic impedance cardiography and arterial blood pressure by auscultation. A repeated measures ANOVA indicated that pretrial caffeine increased oxygen uptake and energy expenditure rate (p < 0.05) but did not change respiratory exchange ratio. Systolic, diastolic, and mean arterial blood pressure were elevated following caffeine intake (p < 0.05). Cardiac output, heart rate, stroke volume, and systemic vascular resistance were not significantly different between caffeine and placebo sessions. For each of the metabolic and hemodynamic variables examined, the effects of caffeine were similar during constant-load, light intensity cycling and at rest. These data illustrate that caffeine's mild thermogenic influence can be mediated without a major shift in substrate oxidation mixture. Caffeine at this dosage level alters cardiovascular dynamics by augmenting arterial blood pressure.

Haloperidol, risperidone and quetiapine in the treatment of acute severe manic episode in bipolar disorder: The experience at the mood disorder unit in Milan

2016 ◽  
Vol 33 (S1) ◽  
pp. S121-S121
Author(s):  
D. Delmonte ◽  
C. De Santis ◽  
S. Brioschi ◽  
B. Barbini ◽  
C. Colombo
Keyword(s):  
Repeated Measures ◽  
Best Practice ◽  
Rating Scale ◽  
Manic Episode ◽  
Drug Dose ◽  
Mood Stabilizers ◽  
Young Mania ◽  
Double Blind ◽  
Competing Interest ◽  
Double Blind Design

IntroductionPatients affected by severe manic episode, often with delusional symptoms, are commonly treated with a combination of mood stabilizers, antipsychotics and other sedatives. The choice of a specific drug, dose and term is still debated.ObjectivesA naturalistic study on a sample of 84 inpatients affected by acute severe mania treated with a combination therapy.AimsTo compare efficacy and tolerability of haloperidol/risperidone/quetiapine in association with lithium and/or valproate.MethodsEighty-four bipolar inpatients affected by a manic episode according to DSM-5 criteria. Drugs administered according to our best practice. Clinical course weekly monitored with Young Mania Rating Scale (YMRS) for 4weeks. Extrapiramidal side effects (EPSE) monitored with Saint Hans Rating Scale (SHRS).ResultsTwenty-five men (29.76%) and 59 women (70.24%); mean age 43.37 ± 13.58 years. Mean YMRS score T0 40.27 ± 9.04. Forty-one patients (48.81%) treated with haloperidol (3.4 mg/die); 16 (19.05%) with risperidone (4.3 mg/die); 27 (32.14%) with quetiapine (438 mg/die). The 3 groups showed no difference regarding clinical characteristics and YMRS basal scores. Chi2 analysis confirmed an higher response rate (50% of reduction of YMRS final score compared to T0) with haloperidol (χ2 = 14.88; P = 0.00). The repeated-measures model analysis showed a significant decrease (P < 0.05) in YMRS scores in haloperidol vs. risperidone vs. quetiapine patients for all time points from second week. No statistical difference for EPSE was found.ConslusionsWe suggest that haloperidol could be advisable in the treatment of severe mania, with rapid efficacy, even with low doses. Occurrence of EPSE was not considerable during the acute treatment. Studies with a larger sample size, randomization, fixed doses, double blind design are needed.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Caffeine-dependent changes of sleep-wake regulation: evidence for adaptation after repeated intake

2019 ◽  
Author(s):  
Janine Weibel ◽  
Yu-Shiuan Lin ◽  
Hans-Peter Landolt ◽  
Corrado Garbazza ◽  
Vitaliy Kolodyazhniy ◽  
...  
Keyword(s):  
Time Course ◽  
Area Under The Curve ◽  
Time Of Day ◽  
Caffeine Intake ◽  
Daily Consumption ◽  
Double Blind ◽  
Circadian Phase ◽  
Clear Cut ◽  
Caffeine Withdrawal ◽  
Attentional Lapses

AbstractTo enhance wakefulness, daily consumption of caffeine in the morning and afternoon is highly common. However, it is unknown whether such a regular intake pattern affects timing and quality of wakefulness, as regulated by an interplay of circadian and sleep-homeostatic mechanisms. Thus, we investigated the effects of daily caffeine intake and its withdrawal on circadian rhythms and wake-promotion in 20 male young habitual caffeine consumers. We applied a double-blind, within-subject design with a caffeine (150 mg, 3 x daily), a placebo, and a withdrawal condition each lasting ten days. Starting on day nine of treatment, salivary melatonin and cortisol, evening nap sleep, as well as sleepiness and vigilance performance throughout day and night were quantified during 43 h under controlled laboratory conditions. Neither the time course of melatonin (i.e., onset, amplitude, or area under the curve) nor the time course of cortisol were significantly affected by caffeine intake or its withdrawal. During withdrawal, however, volunteers reported increased sleepiness, showed more attentional lapses, as well as polysomnography-derived markers of elevated sleep propensity in the late evening compared to both, placebo and caffeine conditions. Thus, the typical timing of habitual caffeine intake in humans may not necessarily shift circadian phase nor lead to clear-cut benefits in alertness. The time-of-day independent effects of caffeine withdrawal suggest an adaptation to the substance, presumably in the homeostatic aspect of sleep-wake regulation.

scholarly journals Cerebellar rTMS in PSP: a Double-Blind Sham-Controlled Study Using Mobile Health Technology

2021 ◽  
Author(s):  
Andrea Pilotto ◽  
Maria Cristina Rizzetti ◽  
Alberto Lombardi ◽  
Clint Hansen ◽  
Michele Biggi ◽  
...  
Keyword(s):  
Digital Technology ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Health Technology ◽  
Controlled Study ◽  
Double Blind ◽  
Non Invasive ◽  
Lower Back ◽  
Before And After ◽  
Double Blind Design ◽  
Theta Burst

AbstractThere are no effective treatments in progressive supranuclear palsy (PSP). The aim of this study was to test the efficacy of theta burst repetitive transcranial magnetic stimulation (rTMS) on postural instability in PSP. Twenty PSP patients underwent a session of sham or real cerebellar rTMS in a crossover design. Before and after stimulation, static balance was evaluated with instrumented (lower back accelerometer, Rehagait®, Hasomed, Germany) 30-s trials in semitandem and tandem positions. In tandem and semitandem tasks, active stimulation was associated with increase in time without falls (both p=0.04). In the same tasks, device-extracted parameters revealed significant improvement in area (p=0.007), velocity (p=0.005), acceleration and jerkiness of sway (p=0.008) in real versus sham stimulation. Cerebellar rTMS showed a significant effect on stability in PSP patients, when assessed with mobile digital technology, in a double-blind design. These results should motivate larger and longer trials using non-invasive brain stimulation for PSP patients.

scholarly journals Efficacy of galcanezumab in patients with migraine who did not benefit from commonly prescribed preventive treatments

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dulanji K. Kuruppu ◽  
Joshua Tobin ◽  
Yan Dong ◽  
Sheena K. Aurora ◽  
Laura Yunes-Medina ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Migraine Headache ◽  
Mixed Model ◽  
Preventive Treatment ◽  
Response Rates ◽  
Toxin A ◽  
Double Blind ◽  
Preventive Medication ◽  
Onabotulinum Toxin A ◽  
Post Hoc

Abstract Background Galcanezumab is a calcitonin gene-related peptide (CGRP) monoclonal antibody (mAb) indicated for the preventive treatment of migraine. While galcanezumab has demonstrated efficacy in patients who did not respond to prior preventive medications in general, its efficacy in patients who did not benefit from individual, commonly prescribed preventive treatments due to inadequate efficacy or safety/tolerability remains unknown. Methods CONQUER was a 3-month, randomized, double-blind, placebo-controlled, phase 3b study that enrolled patients with episodic or chronic migraine who had 2 to 4 migraine preventive medication category failures in the past 10 years. Patients were randomly assigned 1:1 to receive placebo (N = 230) or galcanezumab 120 mg/month (240 mg loading dose; N = 232). Post hoc analyses were conducted to determine the efficacy of galcanezumab in patients who had not benefited from six of the most commonly prescribed migraine preventive medications. The mean change from baseline in monthly migraine headache days and ≥ 50 % response rates were assessed over months 1–3. Improvement in Migraine-Specific Questionnaire Role Function-Restrictive (MSQ-RFR) scores were assessed at month 3. The endpoints were estimated via mixed model with repeated measures. Results The most common treatment failures due to inadequate efficacy or safety/tolerability, which at least 20 % of patients reported trying without benefit, included topiramate, amitriptyline, propranolol, valproate or divalproex, onabotulinum toxin A, and metoprolol. Patients who had not previously benefited from these treatments had a greater mean reduction in monthly migraine headache days across months 1–3 in the galcanezumab group compared to placebo (all p < 0.01). More patients treated with galcanezumab experienced a ≥ 50 % reduction from baseline in monthly migraine headache days across months 1–3 compared to placebo (all p < 0.05). Galcanezumab-treated patients had a greater improvement in mean MSQ-RFR scores at month 3 compared to placebo (all p < 0.01). Conclusions In this population, galcanezumab was effective in reducing monthly migraine headache days, improving response rates, and enhancing quality of life in patients who had not previously benefited from topiramate, amitriptyline, propranolol, valproate or divalproex, onabotulinum toxin A, and/or metoprolol due to inadequate efficacy or safety/tolerability. Trial registration ClinicalTrials.gov NCT03559257 (CONQUER).

scholarly journals The Composition and Diversity of the Gut Microbiota in Children Is Modifiable by the Household Dogs: Impact of a Canine-Specific Probiotic

2021 ◽  
Vol 9 (3) ◽  
pp. 557
Author(s):  
Carlos Gómez-Gallego ◽  
Mira Forsgren ◽  
Marta Selma-Royo ◽  
Merja Nermes ◽  
Maria Carmen Collado ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Home Environment ◽  
Double Blind ◽  
Before And After ◽  
Probiotic Intervention ◽  
Probiotic Product ◽  
Acid Producing Bacteria ◽  
Double Blind Design ◽  
To Receive ◽  
Gut Microbiota Composition

The development of the infant gut microbiota is initiated during pregnancy and continued through early life and childhood, guided by the immediate environment of the child. Our aim was to characterize the shared microbiota between dogs and children as well as to determine whether introduction to dogs of a dog-specific probiotic combination modifies the transfer process. We studied 31 children from allergic families with pet dog(s) and 18 control families without a dog. Altogether 37 dogs were randomized for a 4-week period in a double-blind design to receive canine-derived probiotic product containing a mixture of L. fermentum, L. plantarum, and L. rhamnosus, or placebo. Fecal samples from children and dogs were taken before and after the treatment. Distinctive gut microbiota composition was observed in children with dogs compared to those without a dog, characterized by higher abundance of Bacteroides and short-chain fatty acid producing bacteria such as Ruminococcus and Lachnospiraceae. Probiotic intervention in dogs had an impact on the composition of the gut microbiota in both dogs and children, characterized by a reduction in Bacteroides. We provide evidence for a direct effect of home environment and household pets on children microbiota and document that modification of dog microbiota by specific probiotics is reflected in children’s microbiota.

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