Exercise modulates both brown adipose tissue (BAT) metabolism and white adipose tissue (WAT) browning in murine models. Whether this is true in humans, however, has remained unknown. An unblinded... Show moreExercise modulates both brown adipose tissue (BAT) metabolism and white adipose tissue (WAT) browning in murine models. Whether this is true in humans, however, has remained unknown. An unblinded randomized controlled trial (ClinicalTrials.gov ID: NCT02365129) was therefore conducted to study the effects of a 24-week supervised exercise intervention, combining endurance and resistance training, on BAT volume and activity (primary outcome). The study was carried out in the Sport and Health University Research Institute and the Virgen de las Nieves University Hospital of the University of Granada (Spain). One hundred and forty-five young sedentary adults were assigned to either (i) a control group (no exercise, n = 54), (ii) a moderate intensity exercise group (MOD-EX, n = 48), or (iii) a vigorous intensity exercise group (VIG-EX n = 43) by unrestricted randomization. No relevant adverse events were recorded. 97 participants (34 men, 63 women) were included in the final analysis (Control; n = 35, MOD-EX; n = 31, and VIG-EX; n = 31). We observed no changes in BAT volume (Delta Control: -22.2 +/- 52.6 ml; Delta MOD-EX: -15.5 +/- 62.1 ml, Delta VIG-EX: -6.8 +/- 66.4 ml; P = 0.771) or F-18-fluorodeoxyglucose uptake (SUVpeak Delta Control: -2.6 +/- 3.1 ml; Delta MOD-EX: -1.2 +/- 4.8, Delta VIG-EX: -2.2 +/- 5.1; p = 0.476) in either the control or the exercise groups. Thus, we did not find any evidence of an exercise-induced change on BAT volume or activity in young sedentary adults.Exercise modulates brown adipose tissue (BAT) metabolism in murine models. Here the authors report that there is no evidence that 24 weeks of supervised exercise training modulates BAT volume or function in young sedentary adults in the ACTIBATE randomized controlled trial. Show less
Jurado-Fasoli, L.; Yang, W.; Kohler, I.; Dote-Montero, M.; Osuna-Prieto, F.J.; Di, X.; ... ; Martinez-Tellez, B. 2022
This study aimed to investigate the effects of different exercise training programs on fasting plasma levels of oxylipins, endocannabinoids (eCBs), and eCBs-like molecules in middle-aged sedentary... Show moreThis study aimed to investigate the effects of different exercise training programs on fasting plasma levels of oxylipins, endocannabinoids (eCBs), and eCBs-like molecules in middle-aged sedentary adults. A 12-week randomized controlled trial was conducted using a parallel group design. Sixty-five middle-aged adults (40???65 years old) were randomly assigned to: (a) no exercise (control group), (b) concurrent training based on international physical activity recommendations (PAR group), (c) highintensity interval training (HIIT group), and (d) HIIT together with whole-body electromyostimulation (HIIT + EMS group). Plasma levels of oxylipins, eCBs, and eCBs-like molecules were determined in plasma samples before and after the intervention using targeted lipidomics. Body composition was assessed through dual-energy X-ray absorptiometry, and dietary intake through a food frequency questionnaire and three nonconsecutive 24-hr recalls. The physical activity recommendations, HIIT, and HIITEMS groups showed decreased plasma levels of omega-6 and omega-3-derived oxylipins, and eCBs and eCBs-like molecules after 12 weeks (all ?? < ???0.12; all p .05). Importantly, after Bonferroni post hoc corrections, the differences in plasma levels of omega-6 and omega-3 oxylipins were not statistically significant compared with the control group (all p .05). However, after post hoc corrections, plasma levels of anandamide and oleoylethanolamide were increased in the physical activity recommendations group compared with the control group (anandamide: ?? = 0.05 vs. ???0.09; oleoylethanolamide: ?? = ???0.12 vs. 0.013, all p < .049). In conclusion, this study reports that a 12-week exercise training intervention, independent of the modality applied, does not modify fasting plasma levels of omega-6 and omega-3 oxylipins, eCBs, and eCBs-like molecules in middle-aged sedentary adults. Show less
Jurado-Fasoli, L.; Yang, W.; Kohler, I.; Dote-Montero, M.; Osuna-Prieto, F.J.; X.Y. di; ... ; Martinez-Tellez, B. 2022
This study aimed to investigate the effects of different exercise training programs on fasting plasma levels of oxylipins, endocannabinoids (eCBs), and eCBs-like molecules in middle-aged sedentary... Show moreThis study aimed to investigate the effects of different exercise training programs on fasting plasma levels of oxylipins, endocannabinoids (eCBs), and eCBs-like molecules in middle-aged sedentary adults. A 12-week randomized controlled trial was conducted using a parallel group design. Sixty-five middle-aged adults (40???65 years old) were randomly assigned to: (a) no exercise (control group), (b) concurrent training based on international physical activity recommendations (PAR group), (c) highintensity interval training (HIIT group), and (d) HIIT together with whole-body electromyostimulation (HIIT + EMS group). Plasma levels of oxylipins, eCBs, and eCBs-like molecules were determined in plasma samples before and after the intervention using targeted lipidomics. Body composition was assessed through dual-energy X-ray absorptiometry, and dietary intake through a food frequency questionnaire and three nonconsecutive 24-hr recalls. The physical activity recommendations, HIIT, and HIITEMS groups showed decreased plasma levels of omega-6 and omega-3-derived oxylipins, and eCBs and eCBs-like molecules after 12 weeks (all ?? < ???0.12; all p .05). Importantly, after Bonferroni post hoc corrections, the differences in plasma levels of omega-6 and omega-3 oxylipins were not statistically significant compared with the control group (all p .05). However, after post hoc corrections, plasma levels of anandamide and oleoylethanolamide were increased in the physical activity recommendations group compared with the control group (anandamide: ?? = 0.05 vs. ???0.09; oleoylethanolamide: ?? = ???0.12 vs. 0.013, all p < .049). In conclusion, this study reports that a 12-week exercise training intervention, independent of the modality applied, does not modify fasting plasma levels of omega-6 and omega-3 oxylipins, eCBs, and eCBs-like molecules in middle-aged sedentary adults. Show less
Objective: To study the association between usual dietary factors (dietary energy density, nutrient intake, food group consumption, and dietary pattern) and brown adipose tissue (BAT) volume/F-18... Show moreObjective: To study the association between usual dietary factors (dietary energy density, nutrient intake, food group consumption, and dietary pattern) and brown adipose tissue (BAT) volume/F-18-fluorodeoxyglucose (F-18-FDG) uptake after personalized cold exposure in young healthy adults.Methods: A total of 122 young adults (n = 82 women; 22.0 +/- 2.1 years old; 24.8 +/- 4.8 kg/m(2)) took part in this cross-sectional study. Dietary factors were measured via a food frequency questionnaire and three non-consecutive 24 h recalls. Dietary energy density (foods and caloric beverages included) and macronutrient intakes were subsequently estimated using EvaIFINUT (R) software, food group consumption was estimated from the food frequency questionnaire, and different dietary patterns and quality indices were determined according to the reference methods. BAT volume, BAT F-18-FDG uptake, and skeletal muscle F-18-FDG uptake were assessed by static F-18-FDG positron-emission tomography and computed tomography (PET-CT) scans after a 2 h personalized exposure to cold.Results: A direct association was detected between dietary energy density and BAT Standardized Uptake Value (SUV)mean (beta = 0.215; R-2 = 0.044; P = 0.022), and between ethanol consumption and BAT volume (beta = 0.215; R-2 = 0.044; P = 0.022). The a priori Mediterranean dietary pattern was inversely associated with BAT SUVmean and SUVpeak (beta = -0.273; R-2 = 0.075; P = 0.003 and beta = -0.255; R-2 = 0.066; P = 0.005 respectively). In addition, the diet quality index for a Mediterranean diet and a pro-inflammatory dietary pattern (as determined via the dietary inflammatory index) were directly associated with BAT SUVmean and SUVpeak (SUVmean: beta = 0.238; R-2 = 0.053; P = 0.013 and beta = 0.256; R-2 = 0.052; P = 0.012 respectively; SUVpeak: beta = 0.278; R-2 = 0.073; P = 0.003 and beta = 0.248; R-2 = 0.049; P = 0.016 respectively). After controlling for multiplicity and possible confounders (sex, the evaluation wave and BMI), all the detected associations persisted.Conclusion: Dietary factors are slightly associated with BAT volume and/or F-18-FDG uptake after a personalized cold exposure in young adults. Our results provide an overall picture of the potential relationships between dietary factors and BAT-related variables in humans. (C) 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. Show less
Objective This study aimed to describe the energy expenditure (EE) and macronutrient oxidation response to an individualized nonshivering cold exposure in young healthy adults. Methods Two... Show moreObjective This study aimed to describe the energy expenditure (EE) and macronutrient oxidation response to an individualized nonshivering cold exposure in young healthy adults. Methods Two different groups of 44 (study 1: 22.1 [SD 2.1] years old, 25.6 [SD 5.2] kg/m(2), 34% men) and 13 young healthy adults (study 2: 25.6 [SD 3.0] years old, 23.6 [SD 2.4] kg/m(2), 54% men) participated in this study. Resting metabolic rate (RMR) and macronutrient oxidation rates were measured by indirect calorimetry under fasting conditions in a warm environment (for 30 minutes) and in mild cold conditions (for 65 minutes, with the individual wearing a water-perfused cooling vest set at an individualized temperature adjusted to the individual's shivering threshold). Results In study 1, EE increased in the initial stage of cold exposure and remained stable for the whole cold exposure (P < 0.001). Mean cold-induced thermogenesis (9.56 +/- 7.9 kcal/h) was 13.9% +/- 11.6% of the RMR (range: -14.8% to 39.9% of the RMR). Carbohydrate oxidation decreased during the first 30 minutes of the cold exposure and later recovered up to the baseline values (P < 0.01) in parallel to opposite changes in fat oxidation (P < 0.01). Results were replicated in study 2. Conclusions A 1-hour mild cold exposure individually adjusted to elicit maximum nonshivering thermogenesis induces a very modest increase in EE and a shift of macronutrient oxidation that may underlie a shift in thermogenic tissue activity. Show less
Heart rate variability (HRV) is a non-invasive indicator of autonomic nervous system function. HRV recordings show artefacts due to technical and/or biological issues. The Kubios software is one of... Show moreHeart rate variability (HRV) is a non-invasive indicator of autonomic nervous system function. HRV recordings show artefacts due to technical and/or biological issues. The Kubios software is one of the most used software to process HRV recordings, offering different levels of threshold-based artefact correction (i.e., Kubios filters). The aim of the study was to analyze the impact of different Kubios filters on the quantification of HRV derived parameters from short-term recordings in three independent human cohorts. A total of 312 participants were included: 107 children with overweight/obesity (10.0 +/- 1.1 years, 58% men), 132 young adults (22.2 +/- 2.2 years, 33% men) and 73 middle-aged adults (53.6 +/- 5.2 years, 48% men). HRV was assessed using a heart rate monitor during 10-15 min, and the Kubios software was used for HRV data processing using all the Kubios filters available (i.e., 6). Repeated-measures analysis of variance indicated significant differences in HRV derived parameters in the time-domain (all p < 0.001) across the Kubios filters in all cohorts, moreover similar results were observed in the frequency-domain. When comparing two extreme Kubios filters, these statistical differences could be clinically relevant, e.g. more than 10 ms in the standard deviation of all normal R-R intervals (SDNN). In conclusion, the results of the present study suggest that the application of different Kubios filters had a significant impact on HRV derived parameters obtained from short-term recordings in both time and frequency-domains. Show less
Study Objectives: Short sleep duration and sleep disturbances have been related to obesity and metabolic disruption. However, the behavioral and physiological mechanisms linking sleep and... Show moreStudy Objectives: Short sleep duration and sleep disturbances have been related to obesity and metabolic disruption. However, the behavioral and physiological mechanisms linking sleep and alterations in energy balance and metabolism are incompletely understood. In rodents, sleep regulation is closely related to appropriate brown adipose tissue (BAT) thermogenic activity, but whether the same is true in humans has remained unknown. The present work examines whether sleep duration and quality are related to BAT volume and activity (measured by F-18-FDG) and BAT radiodensity in humans.Methods: A total of 118 healthy adults (69% women, 21.9 +/- 2.2 years, body mass index: 24.9 +/- 4.7 kg/m(2)) participated in this cross-sectional study. Sleep duration and other sleep variables were measured using a wrist-worn accelerometer for seven consecutive days for 24 hours per day. The Pittsburgh Sleep Quality Index was used to assess sleep quality. All participants then underwent a personalized cold exposure to determine their BAT volume, activity, and radiodensity (a proxy of the intracellular triglyceride content), using static positron emission tomography combined with computed tomography (PET/CI) scan.Results: Neither sleep duration nor quality was associated with BAT volume or activity (the latter represented by the mean and peak standardized 18F-FDG uptake values) or radiodensity (all p >.1). The lack of association remained after adjusting the analyses for sex, date of PET/CT, and body composition.Conclusions: Although experiments in rodent models indicate a strong relationship to exist between sleep regulation and BAT function, it seems that sleep duration and quality may not be directly related to the BAT variables examined in the present work. Show less
This 12-week randomized controlled trial investigates the effects of different training modalities on cardiometabolic risk in sedentary, middle-aged adults, and examines whether alterations in... Show moreThis 12-week randomized controlled trial investigates the effects of different training modalities on cardiometabolic risk in sedentary, middle-aged adults, and examines whether alterations in cardiometabolic risk are associated with changes in those health-related variables that are modifiable by exercise training. The study subjects were 71 middle-aged adults (similar to 54 years old; similar to 50% women) who were randomly assigned to one of the following treatment groups: (1) no exercise (control group), (2) concurrent training based on international physical activity recommendations (PAR group), (3) high intensity interval training (HIIT) group, or (4) HIIT plus whole-body electromyostimulation (HIIT+EMS group). A cardiometabolic risk score was calculated based on the International Diabetes Federation's clinical criteria. A significant reduction in cardiometabolic risk was observed for all exercise training groups compared to the control group (all p < 0.05), which persisted after adjusting potential confounders (all p < 0.05). However, the HIIT+EMS group experienced the most significant reduction (p < 0.001). A significant inverse relationship was detected between the change in lean mass and the change in cardiometabolic risk (p = 0.045). A 12-week exercise training programs-especially the HIIT+EMS program-significantly reduced cardiometabolic risk in sedentary, middle-aged adults independent of sex, age, and cardiorespiratory fitness. Show less
Background & aims: Since the discovery of active brown adipose tissue in human adults, non-shivering cold-induced thermogenesis (CIT) has been regarded as a promising tool to combat obesity.... Show moreBackground & aims: Since the discovery of active brown adipose tissue in human adults, non-shivering cold-induced thermogenesis (CIT) has been regarded as a promising tool to combat obesity. However, there is a lack of consensus regarding the method of choice to analyze indirect calorimetry data from a CIT study. We analyzed the impact of methods for data selection and methods for data analysis on measures of cold-induced energy expenditure (EE) and nutrient oxidation rates.Methods: Forty-four young healthy adults (22.1 +/- 2.1 years old, 25.6 +/- 5.2 kg/m(2), 29 women) participated in the study. Resting metabolic rate (RMR), cold-induced thermogenesis (CIT), and cold-induced nutrient oxidation rates were estimated by indirect calorimetry under fasting conditions during 1 h of cold exposure combining air conditioning (19.5-20 degrees C) and a water perfused cooling vest set at a temperature of 4 degrees C above the individual shivering threshold. We applied three methods for data selection: (i) time intervals every 5 min (5min-TI), (ii) the most stable 5-min period of every forth part of the cold exposure (5min-SS-4P), and (iii) the most stable 5-min period of every half part of the cold exposure (5min-SS-2P). Lately we applied two methods for data analysis: (i) area under the curve as a percentage of the baseline RMR (AUC) and; (ii) the difference between EE at the end of the cold exposure and baseline RMR (Last-RMR).Results: Mean overall CIT estimation ranged from 11.6 +/- 10.0 to 20.1 +/- 17.2 %RMR depending on the methods for data selection and analysis used. Regarding methods for data selection, 5min-SS-2P did not allow to observe physiologically relevant phenomena (e.g. metabolic shift in fuel oxidation; P = 0.547) due to a lack of resolution. The 5min-TI and 5min-SS-4P methods for data selection seemed to be accurate enough to observe physiologically relevant phenomena (all P < 0.014), but not comparable for estimating over-all CIT and cold-induced nutrient oxidation rates (P < 0.01). Regarding methods for data analysis, the AUC seemed to be less affected for data artefacts and to be more representative in participants with a non-stable energy expenditure during cold exposure.Conclusions: The methods for data selection and analysis can have a profound impact on CIT and cold-induced nutrient oxidation rates estimations, and therefore, it is mandatory to unify it across scientific community to allow inter-study comparisons. Based on our findings, 5min-TI should be considered the method of choice to study dynamics (i.e. changes across time) of CIT and cold-induced nutrient oxidation rates, while 5min-SS-4P and AUC should be the method of choice when computing CIT and cold-induced nutrient oxidation rates as a single value. (C) 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. Show less
Humans have metabolically active brown adipose tissue (BAT). However, what is the relation between exercise or physical activity with this tissue remains controversial. Therefore, the main aim of... Show moreHumans have metabolically active brown adipose tissue (BAT). However, what is the relation between exercise or physical activity with this tissue remains controversial. Therefore, the main aim of the present study is to examine whether cardiorespiratory fitness and muscular strength are associated with brown adipose tissue (BAT) volume and activity after exposure to cold in young, sedentary adults. Cardiorespiratory fitness was determined in 119 young, healthy, sedentary adults (68% women, age 21.9 +/- 2.1 years, body mass index 25 +/- 4.8 kg/m(2)) via the maximum treadmill exercise test, and their muscular strength assessed by the handgrip strength test and the 1-repetition maximum bench and leg press tests. Some days later, all subjects were exposed to 2 h of personalized exposure to cold and their cold-induced BAT volume and activity determined by a combination of F-18-fluorodeoxyglucose (F-18-FDG) positron emission tomography and computed tomography scan. Cardiorespiratory fitness was associated with neither the BAT volume nor BAT activity (P >= 0.05). However, handgrip strength with respect to lean body mass was positively (though weakly) associated with BAT activity as represented by the F-18-FDG mean standardised uptake value (SUV) (beta = 3.595, R-2 = 0.039, P = 0.031) and SUVpeak value (beta = 15.314, R-2 = 0.037, P = 0.035). The above relationships remained after adjusting for several confounders. No other associations were found. Handgrip strength with respect to lean body mass is positively associated with BAT activity (SUVmean and SUVpeak) in young adults after exposure to cold - but only weakly. Further studies are needed to reveal the relationship between muscular fitness and human BAT characteristics. Show less
Background Brown adipose tissue (BAT) seems to play a role in bone morphogenesis. A negative association has been reported between BAT and bone mineral density (BMD) in women, but not in men. A... Show moreBackground Brown adipose tissue (BAT) seems to play a role in bone morphogenesis. A negative association has been reported between BAT and bone mineral density (BMD) in women, but not in men. A panel of experts has recently published a set of recommendations for BAT assessment, and thus, to re-address previously reported associations is needed. This study aimed to investigate the association between cold-induced BAT (18) F-Fluorodeoxyglucose (F-18-FDG) uptake and BMD in young healthy adults.Methods Ninety-eight healthy adults (68 women; 22 +/- 2.2 years old; 24.3 +/- 4.5 kg/m(2)) cold-induced BAT was assessed by means of an F-18-FDG positron emission tomography-computed tomography (PET-CT) scan preceded by a personalized cold stimulation. The cold exposure consisted in 2 h in a mild cold room at 19.5-20 degrees C wearing a water perfused cooling vest set 4 degrees C above the individual shivering threshold. Total body and lumbar spine BMD were assessed by a whole-body DXA scan.Results We found no association between BMD and cold-induced BAT volume, mean, and maximal activity (all P>0.1) in neither young and healthy men nor women. These results remained unchanged when adjusting by height, by body composition, and by objectively assessed physical activity. Sensitivity analyses using the criteria to quantify cold-induced BAT-related parameters applied in previous studies did not change the results.Conclusions In summary, our study shows that there is no association between cold-induced BAT and BMD in young healthy adults. Moreover, our data support the notion that previously shown associations between BAT and BMD in healthy non-calorically restricted individuals, could be driven by methodological issues related to BAT assessment and/or sample size limitations. Show less
The time spent in sedentary behaviour represents an important public health burden. To reduce sedentary time in the general population, the simplest, most effective, and most accessible method is... Show moreThe time spent in sedentary behaviour represents an important public health burden. To reduce sedentary time in the general population, the simplest, most effective, and most accessible method is to decrease lying and sitting time. We aimed to compare differences on energy expenditure (EE) across lying, sitting, and standing positions; and to analyse the associations between the change on EE of changing from one position to another and anthropometric and body composition parameters in young healthy adults. A total of 55 (69% women) young healthy adults aged 21.7 +/- 2.2 participated in the study. We measured EE by indirect calorimetry across lying, sitting, and standing positions following the standard procedures. The EE was significantly higher in standing than in both lying and sitting positions (mean difference: 0.121 +/- 0.292 and 0.125 +/- 0.241 kcal/min, respectively; all P<0.001), and no differences were observed between lying and sitting positions (P = 1.000). There was a negative association between the EE differences in sitting vs. standing position and lean body mass (P = 0.048), yet no associations between EE differences with the rest of the anthropometric and body composition parameters were observed in each position pair studied (all P>0.321). Our findings support the fact that increasing the time spent standing could be a simple strategy to slightly increase EE. Therefore, our results have important clinical implications including a better monitoring, characterizing, and promoting countermeasures to sedentariness through low-level physical activities. Show less
Introduction: The ageing process can be influenced by different dietary patterns and dietary factors.Aim: To analyse the association of dietary factors, which include the Mediterranean diet... Show moreIntroduction: The ageing process can be influenced by different dietary patterns and dietary factors.Aim: To analyse the association of dietary factors, which include the Mediterranean diet adherence, the compliance with the "Sociedad Espanola de Nutricion Comunitaria" food portion recommendations, and the intake of different food groups, with the secreted form of the alpha-Klotho gene (S-Klotho as an anti-ageing marker) in middle-aged sedentary adults.Methods: A total of 74 (39 women) middle-aged sedentary adults participated in the study. Dietary factors were assessed with a food frequency questionnaire and the PREDIMED questionnaire. The S-Klotho plasma levels were measured using a soluble alpha-Klotho ELISA assay kit.Results: We observed: (i) a negative association between the adherence to the Mediterranean diet and the S-Klotho plasma levels (beta = - 53.219; R-2 = 0.078; P = 0.020), (ii) a higher intake of wine (> 7 glasses/week), was associated with lower S-Klotho plasma levels (P = 0.039), and (iii) a positive association between nuts portion intake and the S-Klotho plasma levels (beta = 26.087; R-2 = 0.070; P = 0.029). All the associations disappeared after controlling for lean mass index (LMI) (all P > 0.05).Conclusion: Our study suggests that, although dietary factors could be related to S-Klotho plasma levels in middle-aged sedentary adults, LMI is the main determinant in this regard. Show less
The maximal fat oxidation (MFO), and the exercise intensity that elicits MFO (Fat(max)), are considered excellent markers of fat metabolism during exercise. Besides individual's biological... Show moreThe maximal fat oxidation (MFO), and the exercise intensity that elicits MFO (Fat(max)), are considered excellent markers of fat metabolism during exercise. Besides individual's biological characteristics (e.g. fed state, physical fitness level, sex, or age), data selection and analysis can affect MFO and Fatmax estimations, yet the effect is unknown. We investigated (i) the impact of using a pre-defined time interval on MFO and Fat(max) estimation, and (ii) the impact of applying 2 different data analysis approaches (measured-values vs. polynomial-curve) on MFO and Fat(max) estimations in sedentary adults. A total of 151 (97 women) sedentary adults aged 29.2 +/- 13.2 years old participated in the study. We assessed MFO and Fatmax through a walking graded exercise test using indirect calorimetry. We pre-defined 13 different time intervals for data analysis, and the estimation of MFO and Fat(max) were performed through the measured-values and the polynomial-curve data analysis approaches. There were significant differences in MFO across pre-defined time intervals methods (P < 0.001) applying measured-values data analysis approach, while no statistical differences were observed when using polynomial-curve data analysis approach (P = 0.077). There were no differences in Fat(max) across pre-defined time intervals independently of the data analysis approach (P >= 0.7). We observed significant differences in MFO between measured-values and the polynomial-curve data analysis approaches across the time intervals methods selected (all P <= 0.05), and no differences were observed in Fat(max) (all P >= 0.2). In conclusion, our results revealed that there are no differences in MFO and Fat(max) across different time intervals methods selected using the polynomial-curve data analysis approach. We observed significant differences in MFO between measured-values vs. polynomial-curve data analysis approaches in all the study time intervals, whereas no differences were detected in Fatmax. Therefore, the use of polynomial-curve data analysis approach allows to compare MFO and Fat(max) using different time intervals in sedentary adults. Show less
Purpose: Human brown adipose tissue (BAT) has gained considerable attention as a potential therapeutic target for obesity and type 2 diabetes; however, whether physical activity (PA) might be an... Show morePurpose: Human brown adipose tissue (BAT) has gained considerable attention as a potential therapeutic target for obesity and type 2 diabetes; however, whether physical activity (PA) might be an efficient stimulus to activate and recruit BAT remains to be ascertained. We aimed to examine whether objectively measured PA levels were associated with BAT volume and activity in young sedentary adults. We additionally examined the association of PA levels with the skeletal muscles activity.Methods: A total of 130 young healthy and sedentary adults (67% women; age, 21.9 +/- 2.1 years old; body mass index, 25 +/- 4.8 kg/m(2)) participated in this cross-sectional study. PA was objectively measured with a wrist-worn accelerometer for 7 consecutive days. Age-specific cut points were applied to classify wrist accelerations into sedentary time and different PA intensities (i.e., light, moderate, vigorous, moderate-vigorous). The participants underwent 2 hours of a personalized cold exposure to determine the cold-induced BAT volume and activity and the skeletal muscles activity by means of an F-18 fluorodeoxyglucose positron emission tomography combined with a CT scan.Results: Objectively measured PA intensity levels were neither associated with BAT volume and activity nor with the skeletal muscles activity (all P> 0.05). The results remained after adjusting for sex, waking time, and environmental temperature.Conclusions: Although PA plays an important role in the prevention of obesity and related comorbidities, it seems that other physiological mechanisms rather than brown adipocyte activation or recruitment might moderate its beneficial metabolic effects in young sedentary adults. Show less
Having valid and reliable resting energy expenditure (REE) estimations is crucial to establish reachable goals for dietary and exercise interventions. However, most of the REE predictive equations... Show moreHaving valid and reliable resting energy expenditure (REE) estimations is crucial to establish reachable goals for dietary and exercise interventions. However, most of the REE predictive equations were developed some time ago and, as the body composition of the current population has changed, it is highly relevant to assess the validity of REE predictive equations in contemporary young adults. In addition, little is known about the role of sex and weight status on the validity of these predictive equations. Therefore, this study aimed to investigate the role of sex and weight status in congruent validity of REE predictive equations in young adults. A total of 132 young healthy adults (67.4% women, 18-26 years old) participated in the study. We measured REE by indirect calorimetry strictly following the standard procedures, and we compared it to 45 predictive equations. The most accurate equations were the following: (i) the Schofield and the Food and Agriculture Organization of the United Nations/World Health Organization/United Nations (FAO/WHO/UNU) equations in normal weight men; (ii) the Mifflin and FAO/WHO/UNU equations in normal weight women; (iii) the Livingston and Korth equations in overweight men; (iv) the Johnstone and Frankenfield equations in overweight women; (v) the Owen and Bernstein equations in obese men; and (vi) the Owen equation in obese women. In conclusion, the results of this study show that the best equation to estimate REE depends on sex and weight status in young healthy adults. Show less
