Impact of an intermittent and localized cooling intervention on skin temperature, sleep quality and energy expenditure in free-living, young, healthy adults

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 = 0.051). 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.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

Physiological responses to acute cold exposure in young lean men

The aim of this study was to comprehensively describe the physiological responses to an acute bout of mild cold in young lean men (n = 11, age: 23 ± 2 years, body mass index: 23.1 ± 1.2 kg/m2) to better understand the underlying mechanisms of non-shivering thermogenesis and how it is regulated. Resting energy expenditure, substrate metabolism, skin temperature, thermal comfort perception, superficial muscle activity, hemodynamics of the forearm and abdominal regions, and heart rate variability were measured under warm conditions (22.7 ± 0.2ÊC) and during an individualized cooling protocol (air-conditioning and water cooling vest) in a cold room (19.4 ± 0.1ÊC). The temperature of the cooling vest started at 16.6ÊC and decreased ~ 1.4ÊC every 10 minutes until participants shivered (93.5 ± 26.3 min). All measurements were analysed across 4 periods: warm period, at 31% and at 64% of individualÂs cold exposure time until shivering occurred, and at the shivering threshold. Energy expenditure increased from warm period to 31% of cold exposure by 16.7% (P = 0.078) and to the shivering threshold by 31.7% (P = 0.023). Fat oxidation increased by 72.6% from warm period to 31% of cold exposure (P = 0.004), whereas no changes occurred in carbohydrates oxidation. As shivering came closer, the skin temperature and thermal comfort perception decreased (all P<0.05), except in the supraclavicular skin temperature, which did not change (P>0.05). Furthermore, the superficial muscle activation increased at the shivering threshold. It is noteworthy that the largest physiological changes occurred during the first 30 minutes of cold exposure, when the participants felt less discomfort.The study was supported by the Spanish Ministry of Economy and Competitiveness (PTA 12264-I), Fondo de InvestigacioÂn Sanitaria del Instituto de Salud Carlos III (PI13/01393), and Retos de la Sociedad (DEP2016-79512-R), Fondos Estructurales de la UnioÂn Europea (FEDER), by the Spanish Ministry of Education (FPU 13/04365 and 15/04059), by the FundacioÂn Iberoamericana de NutricioÂn (FINUT), by the Redes temaÂticas de investigacioÂn cooperativa RETIC (Red SAMI

Concurrent validity of supraclavicular skin temperature measured with iButtons and infrared thermography as a surrogate marker of brown adipose tissue

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 < 0.05) after the shivering threshold test. Moreover, we did not find any association between supraclavicular skin temperature measured with iButtons or IRT and BAT 18F-FDG activity (r = −0.213; P = 0.530 and r = −0.079; P = 0.817). However, we observed a negative association of supraclavicular skin temperature measured by IRT with BAT 18F-FDG volume (r = −0.764; P = 0.006), but not with supraclavicular skin temperature measured with iButtons (r = −0.546; P = 0.082). In light of these results, we concluded that the measurement of skin temperature obtained by iButtons and IRT are not comparable. Furthermore, it seems that supraclavicular skin temperature is not associated with BAT 18F-FDG activity, but it appears to be negatively associated with BAT 18F-FDG volume in the case of IRT.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

Impact of Using Different Levels of Threshold-Based Artefact Correction on the Quantification of Heart Rate Variability in Three Independent Human Cohorts

The following are available online at https://www.mdpi.com/2077-0383/9/2/325/s1, Figure S1: Example of a visual inspection of a R-R signal to find possible artefacts or premature contractions across Kubios filters; Figures S2 and S3: Differences on the Heart Rate Variability (HRV) time- and frequency-domains parameters respectively without considering the Very Strong filter; Figure S4: Differences between cohorts on the SDNN using different Kubios filters; Figure S5: Differences between cohorts on the pNN50 using different Kubios filters; and Figure S6: Differences between cohorts on the HF using different Kubios filters.Juan M.A. Alcantara, Abel Plaza-Florido, Jairo H. Migueles, Guillermo Sanchez-Delgado and Francisco J. Amaro-Gahete are supported by the Spanish Ministry of Education, Culture and Sport (FPU15/04059, FPU16/02760, FPU15/02645, FPU13/04365 and FPU14/04172 respectively). Guillermo Sanchez-Delgado is supported by the University of Granada Plan Propio de Investigación 2018 (Programa Contratos-Puente and Programa Perfeccionamiento de Docotres). Francisco J. Amaro-Gahete is supported by the University of Granada Plan Propio de Investigación 2019 (Programa Contratos-Puente). Guillermo Sanchez-Delgado and Borja Martinez-Tellez are supported by individual postdoctoral grants from the Fundación Alfonso Martin Escudero.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 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.The study was funded by the Spanish Ministry of Economy and Competitiveness (DEP2013-47540 and DEP2016-79512-R), the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI13/01393), European Union Development Funds, the Fundación Iberoamericana de Nutrición (FINUT), the Redes Temáticas de Investigación Cooperativa RETIC (Red SAMID RD16/0022), the University of Granada Plan Propio de Investigación 2016 (Excellence actions: Unit of Excellence on Exercise and Health [UCEES]), and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades (FEDER: ref. SOMM17/6107/UGR)

Sex-specific dose–response effects of a 24-week supervised concurrent exercise intervention on cardiorespiratory fitness and muscular strength in young adults: The ACTIBATE randomized controlled trial

Concurrent training has been postulated as an appropriate time-efficient strategy to improve physical fitness, yet whether the exercise-induced adaptations are similar in men and women is unknown. An unblinded randomized controlled trial was conducted to investigate sex-specific dose–response effects of a 24-week supervised concurrent exercise training program on cardiorespiratory fitness and muscular strength in young adults. One hundred and forty-four sedentary adults aged 18–25 years were assigned to either (i) a control group (n = 54), (ii) a moderate intensity exercise group (MOD-EX, n = 46), or (iii) a vigorous intensity exercise group (VIG-EX, n = 44) by unrestricted randomization. Cardiorespiratory fitness (VO2max), hand grip strength, and one-repetition maximum of leg press and bench press were evaluated at baseline and after the intervention. A total of 102 participants finished the intervention (Control, n = 36; 52% women, MOD-EX, n = 37; 70% women, and VIG-EX, n = 36; 72% women). In men, VO2max significantly increased in the MOD-EX (~8%) compared with the control group and in the VIG-EX group after the intervention (~6.5%). In women, VO2max increased in the MOD-EX and VIG-EX groups (~5.5%) compared with the control group after the intervention. There was a significant increment of leg press in the MOD-EX (~15.5%) and VIG-EX (~18%) groups compared with the control group (~1%) in women. A 24-week supervised concurrent exercise was effective at improving cardiorespiratory fitness and lower body limbs muscular strength in young women—independently of the predetermined intensity—while only at moderate intensity improved cardiorespiratory fitness in menRYC-2010- 05957; Spanish Ministry of Education, Grant/Award Number: FPU 13/04365University of Granada (Beca de Iniciación a la Investigación); Fundación Iberoamericana de Nutrición (FINUT)Redes Temáticas de Investigación Cooperativa RETIC, Grant/AwardRedes Temáticas de Investigación Cooperativa RETIC, Grant/Award Number: Red SAMID RD12/0026/0015AstraZeneca HealthCare Foundation; Vegenat®; Funding for open access charge, Grant/Award Number: UniversidaddeGranada/CBU