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It is unknown how plasma leptin affects fat oxidation depending on sex in young adults. Therefore, the present cross-sectional study aimed to examine the associations of plasma leptin with resting fat oxidation (RFO), maximal fat oxidation during exercise (MFO), and insulin sensitivity, considering the different responses in men and women, and the mediating role of fatness and cardiorespiratory fitness (CRF). Sixty-five young adults (22.5 ± 4.3 years; body mass index = 25.2 ± 4.7 kg·m−2, 23 females) participated in this study. Fasting plasma glucose, insulin, and leptin were analyzed. Variables related to insulin resistance (HOMA1-IR, HOMA2-IR), secretion (HOMA-%β), and sensitivity (HOMA-%S, QUICKI) were computed. RFO and MFO were determined through indirect calorimetry. A peak oxygen uptake (VO2peak) test was performed until exhaustion after the MFO test. The MFO was relativized to body mass (MFO-BM) and the legs’ lean mass divided by the height squared (MFO-LI). In men, leptin was negatively associated with MFO-BM and positively with HOMA-%β (p ≤ 0.02 in both). In women, leptin was positively associated with RFO and QUICKI, and negatively with MFO-BM (p < 0.05 in all). The association between leptin and MFO was mediated by CRF (p < 0.05), but not by fat mass (p > 0.05). Plasma leptin is associated with fat oxidation and insulin secretion/sensitivity, with different responses within each sex. The association between leptin and fat oxidation is mediated by cardiorespiratory fitness.

The FTO rs9939609 gene, which presents three polymorphisms (AA, AT, and TT), has been associated with the development of obesity through an increased fat accumulation; however, the associations of the gene with other physiological mechanisms, such as appetite or fat oxidation, are still unclear. Therefore, this study aims to evaluate the influence of the FTO rs9939609 gene on different obesity-related factors in young adults. The FTO rs9939609 polymorphism was genotyped in 73 participants (28 women, 22.27 ± 3.70 years). Obesity-related factors included dietary assessment, physical activity expenditure, body composition, appetite sensation, resting metabolic rate, maximal fat oxidation during exercise (MFO), and cardiorespiratory fitness. Our results showed that TT allele participants expressed higher values of hunger (p = 0.049) and appetite (p = 0.043) after exercising compared to the AT allele group. Moreover, the TT allele group showed significantly higher values of MFO (p = 0.031) compared to the AT group, regardless of sex and body mass index. Thus, our results suggest that the FTO rs9939609 gene has an influence on appetite, hunger, and fat oxidation during exercise, with TT allele participants showing significantly higher values compared to the AT allele group. These findings may have practical applications for weight loss and exercise programs.

This study aims to analyse sex-specific associations of physical activity and sedentary behaviour with oxidative stress and inflammatory markers in a young-adult population. Sixty participants (21 women, 22.63 ± 4.62 years old) wore a hip accelerometer for 7 consecutive days to estimate their physical activity and sedentarism. Oxidative stress (catalase, superoxide dismutase, glutathione peroxidase, glutathione, malondialdehyde, and advanced oxidation protein products) and inflammatory (tumour necrosis factor-alpha and interleukin-6) markers were measured. Student t-tests and single linear regressions were applied. The women presented higher catalase activity and glutathione concentrations, and lower levels of advanced protein-oxidation products, tumour necrosis factor-alpha, and interleukin-6 than the men (p < 0.05). In the men, longer sedentary time was associated with lower catalase activity (β = −0.315, p = 0.04), and longer sedentary breaks and higher physical-activity expenditures were associated with malondialdehyde (β = −0.308, p = 0.04). Vigorous physical activity was related to inflammatory markers in the women (tumour necrosis factor-alpha, β = 0.437, p = 0.02) and men (interleukin−6, β = 0.528, p < 0.01). In conclusion, the women presented a better redox and inflammatory status than the men; however, oxidative-stress markers were associated with physical activity and sedentary behaviours only in the men. In light of this, women could have better protection against the deleterious effect of sedentarism but a worse adaptation to daily physical activity.

The aim of this study was to assess antioxidant markers before and after a mid-season of professional soccer players from the 3rd Spanish Division, and to correlate antioxidant markers with competitive performance. Sixty-five male players (age = 25.3 ± 4.2 yr, body mass = 73.2 ± 6.7 kg, body height = 177.8 ± 5.7 cm) from three soccer clubs from Cádiz (Spain) participated in the study. Body composition, maximal aerobic capacity (VO2max), and baseline antioxidant blood markers (Total Antioxidant Status (TAS) and Reduced glutathione/Oxidized glutathione ratio) were assessed in the first week of the championship season (pre-test) and after 18 weeks in the mid-season (post-test). Soccer performance was registered according to the official classification ranking at both the mid-season and at the end of the season; ranking positions for Team A were 2nd and 1st, for Team B were 5th and 5th, while for Team C were 12th and 14th, respectively. Regression analyses showed that TAS and VO2max were able to independently predict (p < 0.05) performance in our participants. Moreover, antioxidant levels showed significant main effects on performance (p < 0.001); where a higher antioxidant capacity was observed in the best performance soccer team, both before and after the mid-season. Notwithstanding, the competitive period compromised the antioxidant status since TAS levels significantly decreased after the 18-week training program and competition compared with baseline values in all soccer teams (p < 0.001). These results suggest the need of monitoring antioxidants in soccer players to prevent excessive oxidative stress and cellular damage which could compromise success in competition, by adjusting the training loads, diet or ergogenic aids, if needed.

The physical activity (PA) and inactivity of family caregivers of cancer patients were investigated and related to burden and quality of life through a cross-sectional multicentre study. A total of 75 caregivers were recruited from June 2020 to March 2021. The levels of PA and inactivity were estimated with a wrist accelerometer, 24 h a day, for 7 consecutive days. The Quality of Life Family Version, the Caregiver Strain Index, the total duration of care, the average number of hours spent in care, and the assistance received were registered. Our results showed that moderate-to-vigorous PA was 96.40 ± 46.93 min/day, with 90.7% of participants performing more than 150 min/week of physical activity, and this was significantly associated with age (r = −0.237). Daily inactivity was 665.78 ± 94.92 min, and inactivity for 20–30 min was significantly associated with caregiver burden (r = 0.232) and quality of life (r = −0.322). Compliance with the World Health Organization recommendations was significantly associated with a lower quality of life (r = −0.269). The strength of these associations was limited (r ~0.2). In conclusion, the PA performed by most caregivers met the established recommendations, although older caregivers (>65 years old) performed lower moderate-to-vigorous PA than younger ones. In addition, the mean inactive time was high (11 h/day), showing slight relationships with the burden and quality of life of caregivers.

This study aims to evaluate the differences in body composition, physical function, and physical activity between pre-frail/frail older adults and to detect risk and protective factors against frailty and physical frailty. Fried’s criteria for frailty and physical frailty using the short-performance physical battery (SPPB) were measured in 179 older participants (75.3 ± 6.4 years old). Body weight, height, and waist, arm, and leg circumferences were obtained as body composition variables. Daily accelerometer outcomes (physical activity and inactivity) were obtained. Pre-frail participants showed overall better physical function and spent more time in physical activity and less time in long inactivity periods than frail participants (p < 0.05). Risk frailty factors were higher waist perimeter (Odds Ratio [OR]: 1.032, 95%CI: 1.003–1.062), low leg performance (OR: 1.025, 95%CI: 1.008–1.043), and inactivity periods longer than 30 min (OR:1.002, 95%CI: 1.000–1.005). Protective factors were standing balance (OR:0.908, 95%CI: 0.831–0.992) and SPPB score (OR: 0.908, 95%CI: 0.831–0.992) for frailty, handgrip strength (OR: 0.902, 95%CI: 0.844–0.964) for physical frailty, and light (OR: 0.986, 95%CI: 0.976–0.996) and moderate-to-vigorous (OR: 0.983, 95%CI: 0.972–0.996) physical activity for both. Our findings suggest that handgrip strength, balance, and physical activity are protective frailty factors and can be monitored in pre-frail older adults. Moreover, poor lower body performance and long inactivity periods are frailty risk factors, which highlights their importance in frailty assessment.

The study was funded by the Spanish Ministry of Economy and Competitiveness via the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III (PI13/01393 and CB16/10/00239) and PTA 12264-I, Retos de la Sociedad (DEP2016-79512-R), and European Regional Development Funds (ERDF). Other funders included the Spanish Ministry of Education (FPU 16/05159, 15/04059 and 19/02326), the Fundacion Iberoamericana de Nutricion (FINUT), the Redes Tematicas De Investigacion Cooperativa RETIC (Red SAMID RD16/0022), the AstraZeneca Health Care Foundation, the University of Granada Plan Propio de Investigacion 2016 (Excellence actions: Unit of Excellence on Exercise, Nutrition and Health [UCEENS]), and by the Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF, SOMM17/6107/UGR). AMT was supported by Seneca Foundation through grant 19899/GERM/15 and the Ministry of Science Innovation and Universities RTI2018-093528-B-I0, as well as DJP (MINECO; RYC-2014-16938). BMT was supported by an individual postdoctoral grant from the Fundacion Alfonso Martin Escudero. We thank Dr. Matt Smith of Embr Labs Inc. for configuring the Embr Wave (R) devices used in this experiment., Where people live and work together it is not always possible to modify the ambient temperature; ways must therefore be found that allow individuals to feel thermally comfortable in such settings. The Embr Wave (R) is a wrist-worn device marketed as a 'personal thermostat' that can apply a local cooling stimulus to the skin. The aim of the present study was to determine the effect of an intermittent mild cold stimulus of 25 degrees C for 15-20 s every 5 min over 3.5 days under free-living conditions on 1) skin temperature, 2) perception of skin temperature, 3) sleep quality and 4) resting energy expenditure (REE) in young, healthy adults. Ten subjects wore the device for 3.5 consecutive days. This intervention reduced distal skin temperature after correcting for personal ambient temperature (P < 0.05), but did not affect the subjects' the perception of skin temperature, sleep quality or REE (all P >= 0.051). Thus, this intermittent mild cold regime can reduce distal skin temperature, and wearing it under free-living conditions for 3.5 days does not seem to impair the perception of skin temperature and sleep quality or modify REE., Spanish Ministry of Economy and Competitiveness via the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III PI13/01393 CB16/10/00239, PTA 12264-I, Retos de la Sociedad DEP2016-79512-R, European Commission, Spanish Government 16/05159 15/04059 19/02326, Fundacion Iberoamericana de Nutricion (FINUT), Redes Tematicas De Investigacion Cooperativa RETIC (Red SAMID) RD16/0022, AstraZeneca, University of Granada Plan Propio de Investigacion, Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UGR, Fundacion Seneca 19899/GERM/15, Ministry of Science Innovation and Universities RTI2018-093528-B-I0, MINECO RYC-2014-16938, Fundacion Alfonso Martin Escudero

Background: In contrast to the energy-storing role of white adipose tissue (WAT), brown adipose tissue (BAT) acts as the main site of non-shivering thermogenesis in mammals and has been reported to play a role in protection against obesity and associated metabolic alterations in rodents. Infrared thermography (IRT) has been proposed as a novel non-invasive, safe, and quick method to estimate BAT thermogenic activation in humans. The aim of this study is to determine whether the IRT could be a potential new tool to estimate BAT thermogenic activation in patients with severe obesity in response to bariatric surgery. Methods: Supraclavicular BAT thermogenic activation was evaluated using IRT in a cohort of 31 patients (50 ± 10 years old, BMI = 44.5 ± 7.8; 15 undergoing laparoscopy sleeve gastrectomy and 16 Roux-en-Y gastric bypass) at baseline and 6 months after a bariatric surgery. Clinical parameters were determined at these same time points. Results: Supraclavicular BAT-related activity was detected in our patients by IRT after a cooling stimulus. The BAT thermogenic activation was higher at 6 months after laparoscopy sleeve gastrectomy (0.06 ± 0.1 vs 0.32 ± 0.1), while patients undergoing to a roux-en-Y gastric bypass did not change their thermogenic response using the same cooling stimulus (0.09 ± 0.1 vs 0.08 ± 0.1). Conclusions: Our study postulates the IRT as a potential tool to evaluate BAT thermogenic activation in patients with obesity before and after a bariatric surgery. Further studies are needed to evaluate differences between LSG technique and RYGB on BAT activation. Keywords: Brown adipose tissue; Infrared thermography; Metabolic surgery; Obesity.

Objective: Brown adipose tissue (BAT) is a thermogenic tissue with potential as a therapeutic target in the treatment of obesity and related metabolic disorders. The most used technique for quantifying human BAT activity is the measurement of 18F-fluorodeoxyglucose uptake via a positron emission tomography/computed tomography scan following exposure to cold. However, several studies have indicated the measurement of the supraclavicular skin temperature (SST) by infrared thermography (IRT) to be a less invasive alternative. This work reviews the state of the art of this latter method as a means of determining BAT activity in humans. Methods: The data sources for this review were PubMed, Web of Science, and EBSCOhost (SPORTdiscus), and eligible studies were those conducted in humans. Results: In most studies in which participants were first cooled, an increase in IRT-measured SST was noted. However, only 5 of 24 such studies also involved a nuclear technique that confirmed increased activity in BAT, and only 2 took into account the thickness of the fat layer when measuring SST by IRT. Conclusions: More work is needed to understand the involvement of tissues other than BAT in determining IRTmeasured SST; at present, IRT cannot determine whether any increase in SST is due to increased BAT activity., This study was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) via the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI13/01393), Retos de la Sociedad (DEP2016-79512-R) and European Regional Development Funds (ERDF), the Fundación Iberoamericana de Nutrición (FINUT), the Redes Temáticas de Investigación Cooperativa RETIC (Red SAMID RD16/0022), the AstraZeneca HealthCare Foundation, the University of Granada Plan Propio de Investigación 2016 Excellence actions: Unit of Excellence on Exercise and Health (UCEES), and Plan Propio de Investigación 2018 and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades (ERDF: SOMM17/6107/UGR). DSI is an Investigator of the Miguel Servet Fund from Carlos III National Institute of Health, Spain (CP15/00106). DJP is supported by grants from the Spanish Ministry of Science and Innovation-MINECO (RYC-2014-16938), MINECO/European Fund for Regional Development (FEDER) (DEP2016-76123-R), the Government of Andalusia, the Integrated Territorial Initiative 2014-2020 for the Province of Cádiz (PI-0002-2017), the European Union's ERASMUS+SPORT program (Grant Agreement 603121-EPP-1-2018-1-ES-SPO-SCP), and the EXERNET Research Network on Exercise and Health in Special Populations (DEP2005-00046/ACTI).

We are grateful to Ms. Carmen Sainz-Quinn for assistance with the English language. We are grateful to Alberto Quesada-Aranda for helping with the development of the Temperatus software (Free trial in http://profth.ugr.es/temperatus)., This study is part of a Ph.D. Thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain., Brown adipose tissue (BAT) thermogenic activity is commonly assessed with a positron emission tomography with computed tomography scan (PET/CT). This technique has several limitations and alternative techniques are needed. Supraclavicular skin temperature measured with iButtons and infrared thermography (IRT) has been proposed as an indirect marker of BAT activity. We studied the concurrent validity of skin temperature measured with iButtons vs. IRT and the association of supraclavicular skin temperature measured with iButtons and IRT with BAT. We measured skin temperature upon a shivering threshold test with iButtons and IRT in 6 different regions in 12 participants (n = 2 men). On a separate day, we determined supraclavicular skin temperature with an iButton and IRT after 2 h of a personalized cooling protocol. Thereafter, we quantified BAT volume and activity by PET/CT. We observed that the absolute differences between the devices were statistically different from 0 (all P, This study was supported by the Spanish Ministry of Economy and Competitiveness via the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI13/01393), Retos de la Sociedad (DEP2016-79512-R), PTA 12264-I, and European Regional Development Fund (ERDF), the Spanish Ministry of Education (FPU 13/04365, FPU14/04172, FPU15/05337, and FPU15/04059), by the Spanish Ministry of Science and Innovation-MINECO (RYC-2014-16938), the Fundación Iberoamericana de Nutrición (FINUT), the Redes Temáticas de Investigación Cooperativa RETIC (Red SAMID RD16/0022), the AstraZeneca HealthCare Foundation, the University of Granada Plan Propio de Investigación 2016 -Excellence actions: Unit of Excellence on Exercise and Health (UCEES) - and Plan Propio de Investigación 2018 - Programa Contratos-Puente, and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades (ERDF, ref. SOMM17/6107/UGR). This study is part of a Ph.D.