Effect of sportswear on performance and physiological heat strain during prolonged running in moderately hot conditions.

INTRODUCTION: This study examined the impact of different upper-torso sportswear technologies on the performance and physiological heat strain of well-trained and national-level athletes during prolonged running in moderately hot conditions. METHODS: A randomized crossover design was employed in which 20 well-trained (n = 16) and national-level (n = 4) athletes completed four experimental trials in moderately hot conditions (35°C, 30% relative humidity). In each trial, participants ran at 70% of their peak oxygen uptake (70% V̇O2peak ) for 60 min, while wearing a different upper-body garment: cotton t-shirt, t-shirt with sweat-wicking fabric, compression t-shirt, and t-shirt with aluminum dots lining the inside of the upper back of the garment. Running speed was adjusted to elicit the predetermined oxygen consumption associated with 70% V̇O2peak . Physiological (core and skin temperatures, total body water loss, and urine specific gravity) and perceptual (thermal comfort and sensation, ratings of perceived exertion, and garment cooling functionality) parameters along with running speed at 70% V̇O2peak were continuously recorded. RESULTS: No significant differences were observed between the four garments for running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses (all p > 0.05). The tested athletes reported larger areas of perceived suboptimal cooling functionality in the cotton t-shirt and the t-shirt with aluminum dots relative to the sweat-wicking and compression t-shirts (d: 0.43-0.52). CONCLUSION: There were not differences among the tested garments regarding running speed at 70% V̇O2peak , physiological heat strain, and perceptual responses in well-trained and national-level endurance athletes exercising in moderate heat.

A Neuroprotective Bovine Colostrum Attenuates Apoptosis in Dexamethasone-Treated MC3T3-E1 Osteoblastic Cells.

Glucocorticoid-induced osteoporosis (GIO) is one of the most common secondary forms of osteoporosis. GIO is partially due to the apoptosis of osteoblasts and osteocytes. In addition, high doses of dexamethasone (DEX), a synthetic glucocorticoid receptor agonist, induces neurodegeneration by initiating inflammatory processes leading to neural apoptosis. Here, a neuroprotective bovine colostrum against glucocorticoid-induced neuronal damage was investigated for its anti-apoptotic activity in glucocorticoid-treated MC3T3-E1 osteoblastic cells. A model of apoptotic osteoblastic cells was developed by exposing MC3T3-E1 cells to DEX (0-700 µM). Colostrum co-treated with DEX was executed at 0.1-5.0 mg/mL. Cell viability was measured for all treatment schedules. Caspase-3 activation was assessed to determine both osteoblast apoptosis under DEX exposure and its potential prevention by colostrum co-treatment. Glutathione reduced (GSH) was measured to determine whether DEX-mediated oxidative stress-driven apoptosis is alleviated by colostrum co-treatment. Western blot was performed to determine the levels of p-ERK1/2, Bcl-XL, Bax, and Hsp70 proteins upon DEX or DEX plus colostrum exposure. Colostrum prevented the decrease in cell viability and the increase in caspase-3 activation and oxidative stress caused by DEX exposure. Cells, upon colostrum co-treated with DEX, exhibited higher levels of p-ERK1/2 and lower levels of Bcl-XL, Bax, and Hsp70. Our data support the notion that colostrum may be able to reduce DEX-induced apoptosis possibly via the activation of the ERK pathway and modulation of the Hsp70 system. We provided preliminary evidence on how bovine colostrum, as a complex and multi-component dairy product, in addition to its neuroprotective action, may affect osteoblastic cell survival undergoing apoptosis.

Pharmacological and Non-Pharmacological Agents versus Bovine Colostrum Supplementation for the Management of Bone Health Using an Osteoporosis-Induced Rat Model.

Osteoporosis is defined by loss of bone mass and deteriorated bone microarchitecture. The present study compared the effects of available pharmacological and non-pharmacological agents for osteoporosis [alendronate (ALE) and concomitant supplementation of vitamin D (VD) and calcium (Ca)] with the effects of bovine colostrum (BC) supplementation in ovariectomized (OVX) and orchidectomized (ORX) rats. Seven-month-old rats were randomly allocated to: (1) placebo-control, (2) ALE group (7.5 µg/kg of body weight/day/5 times per week), (3) VD/Ca group (VD: 35 µg/kg of body weight/day/5 times per week; Ca: 13 mg/kg of body weight/day/3 times per week), and (4) BC supplementation (OVX: 1.5 g/day/5 times per week; ORX: 2 g/day/5 times per week). Following four months of supplementation, bone microarchitecture, strength and bone markers were evaluated. ALE group demonstrated significantly higher Ct.OV, Ct.BMC, Tb.Th, Tb.OV and Tb.BMC and significantly lower Ct.Pr, Tb.Pr, Tb.Sp, Ct.BMD and Tb.BMD, compared to placebo (p < 0.05). BC presented significantly higher Ct.Pr, Ct.BMD, Tb.Pr, Tb.Sp, and Tb.BMD and significantly lower Ct.OV, Ct.BMC, Tb.Th, Tb.OV and Tb.BMC compared to ALE in OVX rats (p < 0.05). OVX rats receiving BC experienced a significant increase in serum ALP and OC levels post-supplementation (p < 0.05). BC supplementation may induce positive effects on bone metabolism by stimulating bone formation, but appear not to be as effective as ALE.

Prevalence of uncoupling protein one genetic polymorphisms and their relationship with cardiovascular and metabolic health.

Contribution of UCP1 single nucleotide polymorphisms (SNPs) to susceptibility for cardiometabolic pathologies (CMP) and their involvement in specific risk factors for these conditions varies across populations. We tested whether UCP1 SNPs A-3826G, A-1766G, Ala64Thr and A-112C are associated with common CMP and their risk factors across Armenia, Greece, Poland, Russia and United Kingdom. This case-control study included genotyping of these SNPs, from 2,283 Caucasians. Results were extended via systematic review and meta-analysis. In Armenia, GA genotype and A allele of Ala64Thr displayed ~2-fold higher risk for CMP compared to GG genotype and G allele, respectively (p<0.05). In Greece, A allele of Ala64Thr decreased risk of CMP by 39%. Healthy individuals with A-3826G GG genotype and carriers of mutant allele of A-112C and Ala64Thr had higher body mass index compared to those carrying other alleles. In healthy Polish, higher waist-to-hip ratio (WHR) was observed in heterozygotes A-3826G compared to AA homozygotes. Heterozygosity of A-112C and Ala64Thr SNPs was related to lower WHR in CMP individuals compared to wild type homozygotes (p<0.05). Meta-analysis showed no statistically significant odds-ratios across our SNPs (p>0.05). Concluding, the studied SNPs could be associated with the most common CMP and their risk factors in some populations.

Occupational Heat Stress: Multi-Country Observations and Interventions.

BACKGROUND: Occupational heat exposure can provoke health problems that increase the risk of certain diseases and affect workers' ability to maintain healthy and productive lives. This study investigates the effects of occupational heat stress on workers' physiological strain and labor productivity, as well as examining multiple interventions to mitigate the problem. METHODS: We monitored 518 full work-shifts obtained from 238 experienced and acclimatized individuals who work in key industrial sectors located in Cyprus, Greece, Qatar, and Spain. Continuous core body temperature, mean skin temperature, heart rate, and labor productivity were collected from the beginning to the end of all work-shifts. RESULTS: In workplaces where self-pacing is not feasible or very limited, we found that occupational heat stress is associated with the heat strain experienced by workers. Strategies focusing on hydration, work-rest cycles, and ventilated clothing were able to mitigate the physiological heat strain experienced by workers. Increasing mechanization enhanced labor productivity without increasing workers' physiological strain. CONCLUSIONS: Empowering laborers to self-pace is the basis of heat mitigation, while tailored strategies focusing on hydration, work-rest cycles, ventilated garments, and mechanization can further reduce the physiological heat strain experienced by workers under certain conditions.

Human white-fat thermogenesis: Experimental and meta-analytic findings.

White adipose tissue (WAT) thermogenic activity may play a role in whole-body energy balance and two of its main regulators are thought to be environmental temperature (Tenv) and exercise. Low Tenv may increase uncoupling protein one (UCP1; the main biomarker of thermogenic activity) in WAT to regulate body temperature. On the other hand, exercise may stimulate UCP1 in WAT, which is thought to alter body weight regulation. However, our understanding of the roles (if any) of Tenv and exercise in WAT thermogenic activity remains incomplete. Our aim was to examine the impacts of low Tenv and exercise on WAT thermogenic activity, which may alter energy homeostasis and body weight regulation. We conducted a series of four experimental studies, supported by two systematic reviews and meta-analyses. We found increased UCP1 mRNA (p = 0.03; but not protein level) in human WAT biopsy samples collected during the cold part of the year, a finding supported by a systematic review and meta-analysis (PROSPERO review protocol: CRD42019120116). Additional clinical trials (NCT04037371; NCT04037410) using Positron Emission Tomography/Computed Tomography (PET/CT) revealed no impact of low Tenv on human WAT thermogenic activity (p > 0.05). Furthermore, we found no effects of exercise on UCP1 mRNA or protein levels (p > 0.05) in WAT biopsy samples from a human randomized controlled trial (Clinical trial: NCT04039685), a finding supported by systematic review and meta-analytic data (PROSPERO review protocol: CRD42019120213). Taken together, the present experimental and meta-analytic findings of UCP1 and SUVmax, demonstrate that cold and exercise may play insignificant roles in human WAT thermogenic activity. Abbreviations: WAT:White adipose tissue; Tenv: Environmental temperature; UCP1: Uncoupling protein one; BAT: Brown adipose tissue; BMI:Body mass index; mRNA: Messenger ribonucleic acid; RCT: Randomized controlled trial; WHR: Waist-to-hip ratio; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-analyses; PET/CT: Positron Emission Tomography and Computed Tomography; REE: Resting energy expenditure; 18F-FDG: F18 fludeoxyglucose; VO2peak:Peak oxygen consumption; 1RM: One repetition maximum; SUVmax: Maximum standardized uptake value; Std: Standardized mean difference.

Browning formation markers of subcutaneous adipose tissue in relation to resting energy expenditure, physical activity and diet in humans.

Background Regular exercise and diet may contribute to white adipose tissue (WAT) conversion into a brown adipose-like phenotype that may increase resting energy expenditure (REE), leading to weight loss. We examined the relationship between REE, physical activity (PA) participation and diet with browning formation markers of subcutaneous WAT in healthy men. Materials and methods We assessed REE, diet and body composition of 32 healthy men [age (years): 36.06 ± 7.36, body mass index (BMI): 27.06 ± 4.62 (kg/m2)]. Participants also underwent measurements of PA [metabolic equivalent (MET)-min/week] using the International Physical Activity Questionnaire (IPAQ), while they undertook a subcutaneous fat biopsy from the abdominal region to assess the mRNA expressions of uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator-activated receptor gamma (PPARγ). Results We found no associations between the UCP1, PGC-1α, PPARα and PPARγ mRNAs with REE, PA levels and diet (p > 0.05). However, the PGC-1α, PPARα and PPARγ mRNAs were more expressed in individuals displaying moderate rather than low PA levels (p < 0.05). Furthermore, PGC-1α, PPARα and PPARγ mRNAs were negatively correlated with fat mass percentage (p < 0.05). PGC-1α and PPARα mRNAs were also negatively correlated with BMI, while PGC-1α mRNA was inversely associated with waist-to-hip ratio (p < 0.05). Conclusion REE, PA levels and diet are not associated with browning formation indices of subcutaneous adipose tissue in healthy adult men.