Επιστημονικά Άρθρα

Ioannou LG, Foster J, Morris NB, Piil JF, Havenith G, Mekjavic IB, Kenny GP, Nybo L, & Flouris AD,  (2022). Occupational heat strain in outdoor workers: A comprehensive review and meta-analysis. Temperature, DOI: 10.1080/23328940.2022.2030634 Abstract: The present comprehensive review (i) summarizes the current knowledge on the impacts of occupational heat stress on outdoor workers, (ii) provides a historical background on this issue, (iii) presents a meta-analysis of published data, (iv) explores inter-individual and intra-individual factors, (v) discusses the available heat mitigation strategies, (vi) estimates physical work capacity, labour productivity, and metabolic rate for the year 2030, and (vii) provides an overview of existing policy and legal frameworks on occupational heat exposure. Meta-analytic findings from 38 field studies that involved monitoring 2,409 outdoor workers across 41 jobs in 21 countries suggest that occupational heat stress increases the core (r = 0.44) and skin (r = 0.44) temperatures, as well as the heart rate (r...

Kapnia AK, Dallas CN, Gerodimos V, Flouris AD. Impact of Warm-Up on Muscle Temperature and Athletic Performance. Research Quarterly for Exercise and Sport2022. DOI: 10.1080/02701367.2021.2007212. Abstract: Purpose: We performed two studies to investigate: the minute-by-minute changes in muscle temperature following a 20-min warm-up routine (Study-1) and the impact of the typical post-warm-up period of inactivity on the performance of basketball athletes (Study-2). Method: In Study-1, 26 males (age: 23.6 ± 6.2 yr; BMI: 24.1 ± 3.1 kg/m2) performed a 20-min cycling warm-up and then rested for 20 min. Tibialis anterior muscle temperature was assessed throughout. In Study-2, six male professional basketball players (age: 24.9 ± 4.6 yr; BMI: 25.5 ± 1.8 kg/m2) performed a series of basketball performance tests after a 20-min warm-up, as well as 9-min and 23-min into a post-warm-up period of inactivity. Results: On average, muscle temperature increased by 0.1°C every minute during warm-up and dropped by the same...

Vliora M, Grillo E, Corsini M, Ravelli C, Nintou E, Karligiotou E, Flouris AD, Mitola S. Irisin regulates thermogenesis and lipolysis in 3T3-L1 adipocytes. Biochim Biophys Acta Gen Subj. 2022 Apr;1866(4):130085. doi: 10.1016/j.bbagen.2022.130085. Epub 2022 Jan 10. PMID: 35016977. Abstract: Background: Adipose tissue plays a pivotal role in the development and progression of the metabolic syndrome which along with its complications is an epidemic of the 21st century. Irisin is an adipo-myokine secreted mainly by skeletal muscle and targeting, among others, adipose tissue. In brown adipose tissue it upregulates uncoupling protein-1 (UCP1) which is responsible for mitochondrial non-shivering thermogenesis. Methods: Here we analyzed the effects of irisin on the metabolic activity of 3T3-L1 derived adipocytes through a mitochondrial flux assay. We also assessed the effects of irisin on the intracellular signaling through Western Blot. Finally, the gene expression of ucp1 and lipolytic genes was examined through RT-qPCR. Results: Irisin affects mitochondrial respiration and...

Ioannou LG, Tsoutsoubi L, Mantzios K, Vliora M, Nintou E, Piil JF, Notley SR, Dinas PC, Gourzoulidis GA, Havenith G, Brearley M, Mekjavic IB, Kenny GP, Nybo L, and Flouris AD. Indicators to assess physiological heat strain – Part 3: Multi-country field evaluation and consensus recommendations. Temperature 2022. https://doi.org/10.1080/23328940.2022.2044739. Abstract: In a series of three companion papers published in this Journal, we identify and validate the available thermal stress indicators (TSIs). In this third paper, we conducted field experiments across nine countries to evaluate the efficacy of 61 meteorology-based TSIs for assessing the physiological strain experienced by individuals working in the heat. We monitored 372 experi-enced and acclimatized workers during 893 full work shifts. We continuously assessed core body temperature, mean skin temperature, and heart rate data together with pre/post urine specific gravity and color. The TSIs were evaluated against 17 published criteria covering physiological parameters, practicality, cost effectiveness, and health guidance...

Ioannou LG, Dinas PC, Notley SR, Gofa F, Gourzoulidis GA, Brearley M, Epstein Y, Havenith G, Sawka MN, Bröde P, Mekjavic IB, Kenny GP, Bernard TE, Nybo L, and Flouris AD. Indicators to assess physiological heat strain – part 2: delphi exercise. Temperature 2022. https://doi.org/10.1080/23328940.2022.2044738. Abstract: In a series of three companion papers published in this Journal, we identify and validate the available thermal stress indicators (TSIs). In this second paper of the series, we identified the criteria to consider when adopting a TSI to protect individuals who work in the heat, and we weighed their relative importance using a Delphi exercise with 20 experts. Two Delphi iterations were adequate to reach consensus within the expert panel (Cronbach’s α = 0.86) for a set of 17 criteria with varying weights that should be considered when adopting a TSI to protect individuals who work in the heat. These criteria considered physiological parameters such...

Notley SR, Akerman AP, Friesen BJ, Poirier MP, McCourt E, Flouris A, Kenny GP. Heat tolerance and the validity of occupational heat exposure limits in women during moderate-intensity work. Appl Physiol Nutr Metab. 2022 Mar 8. doi: 10.1139/apnm-2022-0003. Epub ahead of print. PMID: 35259026. Abstract: To mitigate excessive rises in core temperature (>1°C) in non heat-acclimatized workers, the American Conference of Governmental Industrial Hygienists (ACGIH) provide heat stress limits (Action Limit Values; ALV), defined by the wet-bulb globe temperature (WBGT) and a worker's metabolic rate. However, since these limits are based on data from men, their suitability for women remains unclear. We therefore assessed core temperature and heart rate in men (n=19; body surface area-to-mass ratio: 250 (SD 17) cm2/kg) and women (n=15; body surface area-to-mass ratio: 268 (SD 24) cm2/kg) aged 18-45 years during 180-min walking at a moderate metabolic rate (200 W/m2) in WBGTs below (16 and 24°C) and above...

Gourzoulidis GA, Karabetsos E, Bourousis C, Tyrakis C, Flouris AD, Maris TG, Topalis FV. Occupational electromagnetic spectrum hazards and the signif-icance of artificial optical radiation: country report for Greece. Med Lav 2022; 113 (2): e2022016. DOI:10.23749/mdl.v113i2.12636. Abstract: Background: The electromagnetic spectrum spans over an enormous range from 0 up to more than 1020 Hz in the deep ionizing region, significant exposures exist in specific occupational environments. Between the ionizing and the electromagnetic fields (EMF) part of the spectrum, the ‘optical radiation’ (OR) region has specific properties. Comparative and concise evaluation enables action prioritization. Methods: Following the transposition and implementation periods of the artificial optical radiation (AOR) and EMF European Directives, the Hellenic Ministry of Labour in collaboration with the Greek Atomic Energy Commission (EEAE) and the National Technical University of Athens, conducted thorough occupational exposure investigation in Greece. Using dedicated measuring equipment and procedures, the majority of EMF emitting installations in Greece and also AOR...

Flouris AD, Ioannou LG, Notley SR, Kenny GP. Determinants of heat stress and strain in electrical utilities workers across North America as assessed by means of an exploratory questionnaire. J Occup Environ Hyg. 2022 Jan;19(1):12-22. doi: 10.1080/15459624.2021.2001475. Epub 2021 Dec 16. PMID: 34731074. Abstract: Previous field studies monitoring small groups of participants showed that heat stress in the electrical utilities industry may be detrimental to worker health and safety. Our aim in this study was to characterize heat stress and strain in electrical utilities workers across North America. A total of 428 workers in the power generation, transmission, and distribution industry across 16 U.S. states and 3 Canadian Provinces completed a two-part on-line questionnaire anonymously. The first part comprised 13 general questions on the employee's workplace location, role in the organization, years of experience, general duties, average work shift duration, and other job-related information. It also included two questions on self-reported heat stress....

Nintou E, Karligiotou E, Vliora M, Fatouros IG, Jamurtas AZ, Sakellaridis N, Dimas K, Flouris AD. Effects of In Vitro Muscle Contraction on Thermogenic Protein Levels in Co-Cultured Adipocytes. Life (Basel). 2021 Nov 12;11(11):1227. doi: 10.3390/life11111227. PMID: 34833103; PMCID: PMC8625343.  Abstract: The crosstalk between the exercising muscle and the adipose tissue, mediated by myokines and metabolites, derived from both tissues during exercise has created a controversy between animal and human studies with respect to the impact of exercise on the browning process. The aim of this study was to investigate whether co-culturing of C2C12 myotubes and 3T3-L1 adipocytes under the stimuli of electrical pulse stimulation (EPS) mimicking muscle contraction can impact the expression of UCP1, PGC-1a, and IL-6 in adipocytes, therefore providing evidence on the direct crosstalk between adipocytes and stimulated muscle cells. In the co-cultured C2C12 cells, EPS increased the expression of PGC-1a (p = 0.129; d = 0.73) and IL-6 (p...

Foster J, Smallcombe JW, Hodder S, Jay O, Flouris AD, Nybo L, Havenith G. Quantifying the impact of heat on human physical work capacity; part III: the impact of solar radiation varies with air temperature, humidity, and clothing coverage. Int J Biometeorol. 2022 Jan;66(1):175-188. doi: 10.1007/s00484-021-02205-x. Epub 2021 Oct 28. PMID: 34709466; PMCID: PMC8727397. Abstract: Heat stress decreases human physical work capacity (PWC), but the extent to which solar radiation (SOLAR) compounds this response is not well understood. This study empirically quantified how SOLAR impacts PWC in the heat, considering wide, but controlled, variations in air temperature, humidity, and clothing coverage. We also provide correction equations so PWC can be quantified outdoors using heat stress indices that do not ordinarily account for SOLAR (including the Heat Stress Index, Humidex, and Wet-Bulb Temperature). Fourteen young adult males (7 donning a work coverall, 7 with shorts and trainers) walked for 1 h at a...