The human capacity to perform prolonged exercise is impaired in hot environments. To address this issue, a number of studies have investigated behavioral aspects of thermoregulation that are ...recognized as important factors in determining performance. In this review, we evaluated and interpreted the available knowledge regarding the voluntary control of exercise work rate in hot environments. Our analysis indicated that: (a) Voluntary reductions in exercise work rate in uncompensable heat aid thermoregulation and are, therefore, thermoregulatory behaviors. (b) Unlike thermal behavior during rest, the role of thermal comfort as the ultimate mediator of thermal behavior during exercise in the heat remains uncertain. By contrast, the rating of perceived exertion appears to be the key perceptual controller under such conditions, with thermal perception playing a more modulatory role. (c) Prior to increases in core temperature (when only skin temperature is elevated), reductions in self‐selected exercise work rate in the heat are likely mediated by thermal perception (thermal comfort and sensation) and its influence on the rating of perceived exertion. (d) However, when both core and skin temperatures are elevated, factors associated with cardiovascular strain likely dictate the rate of perceived exertion response, thereby mediating such voluntary reductions in exercise work rate.
Introduction
Depression is a very prevalent mental disorder affecting 340 million people globally and is projected to become the leading cause of disability and the second leading contributor to the ...global burden of disease by the year 2020.
Aim
In this paper, we review the evidence published to date in order to determine whether exercise and physical activity can be used as therapeutic means for acute and chronic depression. Topics covered include the definition, classification criteria and treatment of depression, the link between β-endorphin and exercise, the efficacy of exercise and physical activity as treatments for depression, properties of exercise stimuli used in intervention programs, as well as the efficacy of exercise and physical activity for treating depression in diseased individuals.
Conclusions
The presented evidence suggests that exercise and physical activity have beneficial effects on depression symptoms that are comparable to those of antidepressant treatments.
Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide ...up-to-date recommendations to optimise performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimise performance is to heat acclimatise. Heat acclimatisation should comprise repeated exercise-heat exposures over 1-2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimise dehydration during exercise. Following the development of commercial cooling systems (eg, cooling-vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organisers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimising the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events, for hydration and body cooling opportunities, when competitions are held in the heat.
To detect the dependable criteria of behavioural thermoregulation through modelling temperature fluctuations of individuals allowed to freely manipulate inlet water temperature of a liquid ...conditioning garment (LCG) during 130 min of passive exposure to -20 degrees C interspersed with a 10 min period of moderate exercise at the 65th minute using a double-blind experiment.
Eleven volunteers (5 women; 23.40 (SD 2.09) years; BMI: 23.24 (SD 2.19)) who lacked previous experience with LCG and cold exposure experiments.
Despite variations in core and skin temperatures, thermal comfort, thermal sensation, and mean body temperature did not fluctuate significantly over time. Participants were able to find a desired level of LCG inlet temperature within 25 minutes which was maintained at similar levels until the 65th minute of the cold exposure. During exercise, LCG inlet water temperature decreased significantly. Regression models demonstrated that mean skin temperature and change in mean body temperature were significantly associated with thermal comfort and thermal sensation. Subsequent models revealed that, although all temperature variables were associated with LCG inlet water temperature, the coefficient of determination mainly depended on mean skin temperature and change in mean body temperature. The involvement of skin temperature was anticipated as the liquid conditioning garment was in contact with the skin.
Humans generate conscious thermoregulatory responses in resting and exercise conditions during exposures to cold environments that are aimed towards maintaining a threshold mean body temperature, rather than temperature changes in individual body regions.
Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide ...up‐to‐date recommendations to optimize performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimize performance is to heat acclimatize. Heat acclimatization should comprise repeated exercise‐heat exposures over 1–2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimize dehydration during exercise. Following the development of commercial cooling systems (e.g., cooling vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organizers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimizing the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events for hydration and body cooling opportunities when competitions are held in the heat.
The use of protective clothing, whether in space suits, hazardous waste disposal, or sporting equipment, generally increases the risk of heat stress and hyperthermia by impairing the capacity for ...evaporative heat exchange from the body to the environment. To date the most efficient method of microclimate cooling underneath protective clothing has been via conductive heat exchange from circulating cooling fluid next to the skin. In order to make the use of liquid microclimate cooling systems ((LQ)MCSs) as portable and practical as possible, the physiological and biomedical engineering design goals should be towards maximizing the efficiency of cooling to maintain thermal comfort/neutrality with the least cooling possible to minimize coolant and power requirements. Meeting these conditions is an extremely complex task that requires designing for a plethora of different factors. The optimal fitting of the (LQ)MCSs, along with placement and design of tubing and control of cooling, appear to be key avenues towards maximizing efficiency of heat exchange. We review the history and major design constraints of (LQ)MCSs, the basic principles of human thermoregulation underneath protective clothing, and explore potential areas of research into tubing/fabric technology, coolant distribution, and control optimization that may enhance the efficiency of (LQ)MCSs.
Objective: To detect metabolic risk factor cutoff points in adolescence for the diagnosis of metabolic syndrome that develops at the age of 17 years (MS17). Design: This study adopted a 6-year design ...incorporating four data collection time points (TPs). Volunteers were assessed prospectively at the ages of 12, 13, 14 and 17. Participants: A total of 210, 204, 198 and 187 schoolchildren volunteered at the first (TP1=12 years old), second (TP2=13 years old), third (TP3=14 years old) and fourth (TP4=17 years old) data collection TP, respectively. Measurements: At each data collection TP, anthropometrical, biological and lifestyle data were obtained. Identical protocols were used for each assessment conducted by the same trained investigators. Results: A total of 12% of the participants were diagnosed with MS17, the majority of them being boys (P<0.05). The prevalence of the syndrome increased directly with the degree of obesity. Using body mass index (BMI), adiposity and/or aerobic fitness levels in both genders, MS17 could be correctly diagnosed as early as TP1. No such cutoff points were found for high-density lipoprotein cholesterol, triglycerides, blood pressure and fasting plasma glucose levels. Conclusion: With respect to the data presented, it has been established that the calculated longitudinal preventive-screening cutoffs allow successful diagnosis of metabolic syndrome in adolescents using BMI, adiposity or aerobic fitness levels in both sexes. Adoption of such pediatric guidelines may help mitigate future increase in the prevalence of metabolic syndrome.
Summary Objective To investigate the existing evidence about whether adherence to the Mediterranean diet may have a role as an effect modifier of active and passive smoking on human health. Study ...design Review. Methods An overview of emerging evidence and published studies that cover the interaction between the Mediterranean diet and smoking. Results Both epidemiological and laboratory studies have shown that the Mediterranean diet has a protective effect against biochemical and molecular processes that lead to cancer, cardiovascular disease and respiratory illness. Based on the high daily intake of vitamins and antioxidants, the Mediterranean diet is comprised of a number of compounds that could alter certain outcomes related to smoking. Studies have indicated that certain diseases attributable to smoking, such as lung cancer, asthma and cardiovascular disease, are inversely associated with certain antioxidants and lipids. Conclusions The literature indicates that the existence of a partial interaction between adherence to the Mediterranean diet and the health effects of smoking is possible. Further research is needed to lead to a conclusive statement on this hypothesis.
Summary
According to existing literature, bone health in ballet dancers is controversial. We have verified that, compared to controls, young female and male vocational ballet dancers have lower bone ...mineral density (BMD) at both impact and non-impact sites, whereas female professional ballet dancers have lower BMD only at non-impact sites.
Introduction
The aims of this study were to (a) assess bone mineral density (BMD) in vocational (VBD) and professional (PBD) ballet dancers and (b) investigate its association with body mass (BM), fat mass (FM), lean mass (LM), maturation and menarche.
Methods
The total of 152 VBD (13 ± 2.3 years; 112 girls, 40 boys) and 96 controls (14 ± 2.1 years; 56 girls, 40 boys) and 184 PBD (28 ± 8.5 years; 129 females, 55 males) and 160 controls (27 ± 9.5 years; 110 female, 50 males) were assessed at the lumbar spine (LS), femoral neck (FN), forearm and total body by dual-energy X-ray absorptiometry. Maturation and menarche were assessed via questionnaires.
Results
VBD revealed lower unadjusted BMD at all anatomical sites compared to controls (
p
< 0.001); following adjustments for Tanner stage and gynaecological age, female VBD showed similar BMD values at impact sites. However, no factors were found to explain the lower adjusted BMD values in VBD (female and male) at the forearm (non-impact site), nor for the lower adjusted BMD values in male VBD at the FN. Compared to controls, female PBD showed higher unadjusted and adjusted BMD for potential associated factors at the FN (impact site) (
p
< 0.001) and lower adjusted at the forearm (
p
< 0.001). Male PBD did not reveal lower BMD than controls at any site.
Conclusions
Both females and males VBD have lower BMD at impact and non-impact sites compared to control, whereas this is only the case at non-impact site in female PBD. Maturation seems to explain the lower BMD at impact sites in female VBD.
Objective: Maximal oxygen uptake (Vo2max) of 44 ml kg−1 min−1 is an accepted criterion (Vo2CR) below which health and fitness for young male adults may be compromised. New algorithms validated for ...Vo2CR screening using the 20 m multistage shuttle run test (20mMST) were developed. Methods: Vo2max was assessed in 110 males using a stationary gas analyser in a treadmill test (TT) and in 40 of these subjects using a portable gas analyser in the 20mMST. Vo2max predicted from the 20mMST in 70 subjects was used for cross validation. Two equations predicting Vo2max during 20mMST (EQMST) and TT (EQTT) were developed. Results: Significant energy cost variance (ECV) was detected between TT and 20mMST (p<0.001), correlated significantly with subject height, and was a significant predictor of Vo2max differences between TT and 20mMST. The r2 of EQMST was 0.92 (p<0.001). Predicted Vo2max values from EQMST correlated with directly measured 20mMST Vo2max at r = 0.96 (p<0.001). ANOVA detected no mean difference (p>0.05) between predicted and measured values. Prevalence of low fitness based on Vo2CR was 0.37. McNemar χ2 indicated significant differences in sensitivity (p<0.001) and specificity (p<0.05) between the original 20mMST equation (EQLÉG) and EQTT, regarding Vo2CR screening. Cohen’s κ demonstrated higher agreement with TT Vo2max for EQTT (p<0.001) than EQLÉG (p<0.05). TT Vo2max correlated with the end result of both EQLÉG and EQTT at r = 0.75 (p<0.001). Unlike EQTT (p>0.05), mean predicted Vo2max from EQLÉG was significantly higher compared to TT Vo2max (p<0.001). Conclusion: These algorithms increase the efficacy of 20mMST to accurately evaluate aspects of health and fitness.
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