Int J Sport Nutr Exerc Metab
November 2019
Identifying mild dehydration (≤2% of body mass) is important to prevent the negative effects of more severe dehydration on human health and performance. It is unknown whether a single hydration marker can identify both mild intracellular dehydration (ID) and extracellular dehydration (ED) with adequate diagnostic accuracy (≥0.7 receiver-operating characteristic-area under the curve [ROC-AUC]).
View Article and Find Full Text PDFPurpose: Our aim was to investigate lubricin, cartilage oligomeric matrix protein (COMP), and femoral cartilage deformation in response to different biomechanical loading of the knee joint (running vs cycling).
Methods: Serum lubricin and COMP concentrations (enzyme-linked immunosorbent assay), and femoral cartilage thickness (suprapatellar transverse ultrasonography) were determined in 11 male runners (age: 40 ± 6 years; weight: 76 ± 8 kg) and 11 male cyclists (35 ± 12 years; 75 ± 5 kg) at baseline, immediately after, and 30 min after vigorous exercise (time trial: 10-km run or 25-km cycle).
Results: At baseline, lubricin (runners: 104.
Purpose: Research has not convincingly demonstrated the utility of saliva secretory immunoglobulin-A (SIgA) as a biomarker of upper respiratory tract infection (URTI) risk, and disagreement exists about the influence of heavy exercise ("open-window theory") and dehydration on saliva SIgA. Prompted by the search for viable alternatives, we compared the utility of tear and saliva SIgA to predict URTI prospectively (study 1) and assessed the influence of exercise (study 2) and dehydration (study 3) using a repeated-measures crossover design.
Methods: In study 1, 40 subjects were recruited during the common-cold season.
Background: There is evidence that water-loss dehydration is common in older people and associated with many causes of morbidity and mortality. However, it is unclear what clinical symptoms, signs and tests may be used to identify early dehydration in older people, so that support can be mobilised to improve hydration before health and well-being are compromised.
Objectives: To determine the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs and tests to be used as screening tests for detecting water-loss dehydration in older people by systematically reviewing studies that have measured a reference standard and at least one index test in people aged 65 years and over.
Objectives: Dehydration in older adults contributes to increased morbidity and mortality during hospitalization. As such, early diagnosis of dehydration may improve patient outcome and reduce the burden on healthcare. This prospective study investigated the diagnostic accuracy of routinely used physical signs, and noninvasive markers of hydration in urine and saliva.
View Article and Find Full Text PDFPurpose: To examine the effects of intensity and duration of exercise stress on induction of in vivo immunity in humans using experimental contact hypersensitivity (CHS) with the novel antigen diphenylcyclopropenone (DPCP).
Methods: Sixty-four healthy males completed either 30 min running at 60% V˙O2peak (30MI), 30 min running at 80% V˙O2peak (30HI), 120 min running at 60% V˙O2peak (120MI), or seated rest (CON). Twenty min later, the subjects received a sensitizing dose of DPCP; and 4 wk later, the strength of immune reactivity was quantified by measuring the cutaneous responses to a low dose-series challenge with DPCP on the upper inner arm.
Purpose: This study aimed to investigate the effects of multi-strain probiotics supplementation on gastrointestinal permeability, systemic markers of inflammation and running performance when exercising in the heat.
Methods: Ten male runners were randomized to 4 weeks of daily supplementation with a probiotics capsule (45 billion CFU of Lactobacillus, Bifidobacterium and Streptococcus strains) or placebo, separated by a washout period (double-blind, cross-over trial). After each treatment, the runners exercised to fatigue at 80% of their ventilatory threshold at 35 °C and 40% humidity.
Unaccustomed strenuous physical exertion in hot environments can result in heat stroke and acute kidney injury (AKI). Both exercise-induced muscle damage and AKI are associated with the release of interleukin-6, but whether muscle damage causes AKI in the heat is unknown. We hypothesized that muscle-damaging exercise, before exercise in the heat, would increase kidney stress.
View Article and Find Full Text PDFPurpose: It remains unclear whether exercise-induced muscle damage (EIMD) increases heat strain during subsequent exercise heat stress, which in turn may increase the risk of exertional heat illness. We examined heat strain during exercise heat stress 30 min after EIMD to coincide with increases in circulating pyrogens (e.g.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
September 2012
Purpose: To identify if whole-body hydration plays an important role in dry eye (DE). We hypothesized that individuals classified as DE have higher plasma osmolality (Posm), indicating suboptimal hydration, compared with those classified as non-DE.
Methods: Using a hospital-based observational cross-sectional design, assessment of DE and hydration was performed upon admission in 111 participants (N = 56 males and 55 females; mean ± SD age 77 ± 8 years).
Int J Sport Nutr Exerc Metab
June 2012
The purpose was to determine the effects of a carbohydrate (CHO)-protein (PRO) drink, consumed immediately after endurance exercise on saliva anti-microbial proteins known to be important for host defence. Eleven male runners ran for 2 h at 75% VO2max on two occasions, and immediately post-exercise were provided, in randomised order, either a placebo solution (CON), or a CHO-PRO solution containing 1.2 gCHO·kg-1BM and 0.
View Article and Find Full Text PDFInt J Sport Nutr Exerc Metab
June 2012
The purpose of this study was to determine the effects of a carbohydrate (CHO) and protein (PRO) drink consumed immediately after endurance exercise on saliva antimicrobial proteins known to be important for host defense. Eleven male runners ran for 2 hr at 75% VO2max on 2 occasions and immediately postexercise were provided, in randomized order, either a placebo solution (CON) or a CHO-PRO solution containing 1.2 g CHO/kg body mass (BM) and 0.
View Article and Find Full Text PDFAppl Physiol Nutr Metab
October 2012
The aim of the study was to investigate the effect of exercise-induced dehydration and subsequent overnight fluid restriction on saliva antimicrobial proteins important for host defence (secretory IgA (SIgA), α-amylase, and lysozyme). On two randomized occasions, 13 participants exercised in the heat, either without fluid intake to evoke progressive body mass losses (BML) of 1%, 2%, and 3% with subsequent overnight fluid restriction until 0800 h in the following morning (DEH) or with fluids to offset losses (CON). Participants in the DEH trial rehydrated from 0800 h until 1100 h on day 2.
View Article and Find Full Text PDFThe aim of this work was to investigate the effect of a daily mixed nutritional supplement upon body composition, physical performance, and circulating anabolic hormones in soldiers undergoing arduous training. Thirty males received either a habitual diet alone (CON, n = 15) or with the addition of a daily mixed supplement (SUP, n = 15) of ∼5.1 MJ·d⁻¹ during 8 weeks of training.
View Article and Find Full Text PDFThe aim was to investigate the influence of a daily mixed nutritional supplement during an 8-week arduous training programme on immune indices and mediators including circulating leucocyte counts; bacterially stimulated neutrophil degranulation; interleukin-6 (IL-6), cortisol and saliva secretory immunoglobulin-A (SIgA). Thirty men (mean (SD): age 25 (3) years; body mass, 80.9 (7.
View Article and Find Full Text PDFUnlabelled: It has been suggested that tear fluid is isotonic with plasma, and plasma osmolality (P(osm)) is an accepted, albeit invasive, hydration marker. Our aim was to determine whether tear fluid osmolarity (T(osm)) assessed using a new, portable, noninvasive, rapid collection and measurement device tracks hydration.
Purpose: This study aimed to compare changes in T(osm) and another widely used noninvasive marker, urine specific gravity (USG), with changes in P(osm) during hypertonic-hypovolemia.
Heat shock protein 72 (Hsp72) has been detected within saliva, and its presence may contribute to oral defence. It is currently unknown how physiological stress affects salivary Hsp72 or if salivary Hsp72 concentrations reflect plasma Hsp72 concentrations. We studied the effect of exercise upon salivary Hsp72 expression, and using caffeine administration, investigated the role of sympathetic stimulation upon salivary Hsp72 expression.
View Article and Find Full Text PDFCell Stress Chaperones
May 2009
Extra-cellular (e) heat shock protein (Hsp)72 has been shown to be elevated in a number of clinical conditions and has been proposed as a potential diagnostic marker. From a methodological and diagnostic perspective, it is important to investigate if concentrations of eHsp72 fluctuate throughout the day; hence, the purpose of the study was to measure resting concentrations of plasma eHsp72 throughout a 24-h period. Blood samples were taken every hour from 1200-2100 hours and from 0700-1200 hours the following day from seven healthy recreationally active males.
View Article and Find Full Text PDFThe cumulative stressors of exercise manifest themselves at a cellular level by threatening the protein homeostasis of the cell. In these conditions, Heat Shock Proteins (HSP) are synthesised to chaperone mis-folded and denatured proteins. As such, the intracellular HSP response is thought to aid cell survival in the face of otherwise lethal cellular stress.
View Article and Find Full Text PDFObjective: Patients with systemic lupus erythematosus (SLE) have poor physical fitness as measured by maximal oxygen uptake (VO(2max)), which is associated with disability and fatigue. The purpose of this study was to validate, in this population, the Siconolfi Step Test (SST) developed to predict VO(2max) in healthy individuals.
Methods: Thirty patients with well-controlled SLE were tested on a cycle ergometer until volitional exhaustion, and 25 women and 4 men (mean +/- SD age 48 +/- 14 years, weight 71.