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Kenny GP, Groeller H, McGinn R, Flouris AD. Age, human performance, and physical employment standards. Appl Physiol Nutr Metab 2016; 41:S92-S107. [DOI: 10.1139/apnm-2015-0483] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The proportion of older workers has increased substantially in recent years, with over 25% of the Canadian labour force aged ≥55 years. Along with chronological age comes age-related declines in functional capacity associated with impairments to the cardiorespiratory and muscular systems. As a result, older workers are reported to exhibit reductions in work output and in the ability to perform and/or sustain the required effort when performing work tasks. However, research has presented some conflicting views on the consequences of aging in the workforce, as physically demanding occupations can be associated with improved or maintained physical function. Furthermore, the current methods for evaluating physical function in older workers often lack specificity and relevance to the actual work tasks, leading to an underestimation of physical capacity in the older worker. Nevertheless, industry often lacks the appropriate information and/or tools to accommodate the aging workforce, particularly in the context of physical employment standards. Ultimately, if appropriate workplace strategies and work performance standards are adopted to optimize the strengths and protect against the vulnerability of the aging workers, they can perform as effectively as their younger counterparts. Our aim in this review is to evaluate the impact of different individual (including physiological decline, chronic disease, lifestyle, and physical activity) and occupational (including shift work, sleep deprivation, and cold/heat exposure) factors on the physical decline of older workers, and therefore the risk of work-related injuries or illness.
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Affiliation(s)
- Glen P. Kenny
- Human Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, ON K1N 6N5, Canada
| | - Herbert Groeller
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Ryan McGinn
- Human Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, ON K1N 6N5, Canada
| | - Andreas D. Flouris
- Human Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, ON K1N 6N5, Canada
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
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Sakellariou P, Valente A, Carrillo AE, Metsios GS, Nadolnik L, Jamurtas AZ, Koutedakis Y, Boguszewski C, Andrade CMB, Svensson PA, Kawashita NH, Flouris AD. Chronic l-menthol-induced browning of white adipose tissue hypothesis: A putative therapeutic regime for combating obesity and improving metabolic health. Med Hypotheses 2016; 93:21-6. [PMID: 27372851 DOI: 10.1016/j.mehy.2016.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/09/2016] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Obesity constitutes a serious global health concern reaching pandemic prevalence rates. The existence of functional brown adipose tissue (BAT) in adult humans has provoked intense research interest in the role of this metabolically active tissue in whole-body energy balance and body weight regulation. A number of environmental, physiological, pathological, and pharmacological stimuli have been proposed to induce BAT-mediated thermogenesis and functional thermogenic BAT-like activity in white adipose tissue (WAT), opening new avenues for therapeutic strategies based on enhancing the number of beige adipocytes in WAT. HYPOTHESIS Recent evidence support a role of l-menthol cooling, mediated by TRPM8 receptor, on UCP1-dependent thermogenesis and BAT-like activity in classical WAT depots along with the recruitment of BAT at specific anatomical sites. l-Menthol-induced BAT thermogenesis has been suggested to occur by a β-adrenergic-independent mechanism, avoiding potential side-effects due to extensive β-adrenergic stimulation mediated by available beta receptor agonists. l-Menthol has been also linked to the activation of the cold-gated ion channel TRPA1. However, its role in l-menthol-induced UCP1-dependent thermogenic activity in BAT and WAT remains undetermined. White adipose tissue plasticity has important clinical implications for obesity prevention and/or treatment because higher levels of UCP1-dependent thermogenesis can lead to enhanced energy expenditure at a considerable extent. We hypothesize that chronic dietary l-menthol treatment could induce TRPM8- and TRPA1-dependent WAT adaptations, resembling BAT-like activity, and overall improve whole-body metabolic health in obese and overweight individuals. CONCLUSIONS The putative impact of chronic l-menthol dietary treatment on the stimulation of BAT-like activity in classical WAT depots in humans remains unknown. A detailed experimental design has been proposed to investigate the hypothesized l-menthol-induced browning of WAT. If our hypothesis was to be confirmed, TRPM8/TRPA1-induced metabolic adaptations of WAT to BAT-like activity could provide a promising novel therapeutic approach for increasing energy expenditure, regulating body weight, and preventing obesity and its related co-morbidities in humans.
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Affiliation(s)
- Paraskevi Sakellariou
- Institute of Research and Technology Thessaly, Centre for Research and Technology Hellas, Trikala, Greece; FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece
| | - Angelica Valente
- FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece; Department of Human Physiology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Andres E Carrillo
- FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece; Department of Exercise Science, Chatham University, Pittsburgh, PA, USA
| | - George S Metsios
- Faculty of Education, Health and Wellbeing, Wolverhampton University, Walsall Campus, UK
| | - Liliya Nadolnik
- Institute of Biochemistry of Biologically Active Compounds, National Academy of Sciences of Belarus, Grodno, Belarus
| | - Athanasios Z Jamurtas
- FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece
| | - Yiannis Koutedakis
- FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece; Faculty of Education, Health and Wellbeing, Wolverhampton University, Walsall Campus, UK
| | - Cesar Boguszewski
- Endocrine Division (SEMPR), Department of Internal Medicine, Federal University of Parana, Curitiba, Brazil
| | | | - Per-Arne Svensson
- Department of Molecular and Clinical Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Nair Honda Kawashita
- Department of Chemistry, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Andreas D Flouris
- Institute of Research and Technology Thessaly, Centre for Research and Technology Hellas, Trikala, Greece; FAME Laboratory, Department of Exercise Sciences, University of Thessaly, Trikala, Greece.
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Valente A, Carrillo AE, Tzatzarakis MN, Vakonaki E, Tsatsakis AM, Kenny GP, Koutedakis Y, Jamurtas AZ, Flouris AD. The absorption and metabolism of a single L-menthol oral versus skin administration: Effects on thermogenesis and metabolic rate. Food Chem Toxicol 2015; 86:262-73. [PMID: 26429629 DOI: 10.1016/j.fct.2015.09.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 09/24/2015] [Accepted: 09/26/2015] [Indexed: 01/13/2023]
Abstract
We investigated the absorption and metabolism pharmacokinetics of a single L-menthol oral versus skin administration and the effects on human thermogenesis and metabolic rate. Twenty healthy adults were randomly distributed into oral (capsule) and skin (gel) groups and treated with 10 mg kg(-1) L-menthol (ORALMENT; SKINMENT) or control (lactose capsule: ORALCON; water application: SKINCON) in a random order on two different days. Levels of serum L-menthol increased similarly in ORALMENT and SKINMENT (p > 0.05). L-menthol glucuronidation was greater in ORALMENT than SKINMENT (p < 0.05). Cutaneous vasoconstriction, rectal temperature and body heat storage showed greater increase following SKINMENT compared to ORALMENT and control conditions (p < 0.05). Metabolic rate increased from baseline by 18% in SKINMENT and 10% in ORALMENT and respiratory exchange ratio decreased more in ORALMENT (5.4%) than SKINMENT (4.8%) compared to control conditions (p < 0.05). Levels of plasma adiponectin and leptin as well as heart rate variability were similar to control following either treatment (p > 0.05). Participants reported no cold, shivering, discomfort, stress or skin irritation. We conclude that a single L-menthol skin administration increased thermogenesis and metabolic rate in humans. These effects are minor following L-menthol oral administration probably due to faster glucuronidation and greater blood menthol glucuronide levels.
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Affiliation(s)
- Angelica Valente
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Andres E Carrillo
- Department of Exercise Science, Chatham University, Pittsburgh, PA, 15232, USA
| | - Manolis N Tzatzarakis
- Centre of Toxicology Science and Research, Medical School, University of Crete, Heraklion, Greece
| | - Elena Vakonaki
- Centre of Toxicology Science and Research, Medical School, University of Crete, Heraklion, Greece
| | - Aristidis M Tsatsakis
- Centre of Toxicology Science and Research, Medical School, University of Crete, Heraklion, Greece
| | - Glen P Kenny
- Human and Environmental Physiological Research Unit, University of Ottawa, Ontario, Canada
| | - Yiannis Koutedakis
- School of Physical Education and Exercise Science, University of Thessaly, Greece; Institute of Sport, Faculty of Education, Health, and Wellbeing, University of Wolverhampton, WV1 1LY, UK
| | | | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece; Human and Environmental Physiological Research Unit, University of Ottawa, Ontario, Canada.
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