Effects of Intermittent Fasting on Cardiometabolic Health: An Energy Metabolism Perspective

This study was supported by the Spanish Ministry of Universities (FPU18/03357), Fulbright Spain and Junta de Andalucia, a postdoctoral grant from the Fundacion Alfonso Martin Escudero, a Nutrition Obesity Research Center (NORC) grant P30DK072476 and the Louisiana Clinical and Translational Science Center (U54 GM104940).This review summarizes the effects of different types of intermittent fasting (IF) on human cardiometabolic health, with a focus on energy metabolism. First, we discuss the coordinated metabolic adaptations (energy expenditure, hormonal changes and macronutrient oxidation) occurring during a 72 h fast. We then discuss studies investigating the effects of IF on cardiometabolic health, energy expenditure and substrate oxidation. Finally, we discuss how IF may be optimized by combining it with exercise. In general, IF regimens improve body composition, ectopic fat, and classic cardiometabolic risk factors, as compared to unrestricted eating, especially in metabolically unhealthy participants. However, it is still unclear whether IF provides additional cardiometabolic benefits as compared to continuous daily caloric restriction (CR). Most studies found no additional benefits, yet some preliminary data suggest that IF regimens may provide cardiometabolic benefits in the absence of weight loss. Finally, although IF and continuous daily CR appear to induce similar changes in energy expenditure, IF regimens may differentially affect substrate oxidation, increasing protein and fat oxidation. Future tightly controlled studies are needed to unravel the underlying mechanisms of IF and its role in cardiometabolic health and energy metabolism.Spanish Government FPU18/03357Nutrition Obesity Research Center (NORC) P30DK072476Louisiana Clinical and Translational Science Center U54 GM10494

Sleep and Anabolic/Catabolic Hormonal Profile in Sedentary Middle-Aged Adults: The FIT-AGEING Study

Sleep quality plays an important role in the modulation of several aging markers. This influence could be explained by aging-induced hormonal changes. Indeed, poor sleep quality has been associated with the development of several endocrine-related health complications. This study examined the relationship of both subjective and objective sleep quantity and quality, with basal levels of selected plasma anabolic and catabolic hormones in sedentary middle-aged adults. A total of 74 volunteers (52.7% women; aged 53.7 5.1) were recruited for this study. Subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI; higher scores indicate worse sleep quality), and objective sleep quality parameters (total sleep time [TST], wake after sleep onset [WASO], and sleep efficiency [SE]) were measured using a wrist-worn accelerometer. Basal levels of plasma dehydroepiandrosterone sulphate (DHEAS), total testosterone, sex hormone binding globulin (SHBG), somatotropin, and cortisol levels, were determined. Free testosterone was calculated from the total testosterone and SHBG levels. No associations of global PSQI score, TST, WASO, and SE with DHEAS, free testosterone, and somatotropin plasma levels were found, neither in men nor in women (all p 0.05). Global PSQI score was inversely related to cortisol plasma levels in women (p = 0.043). WASO was positively associated with cortisol plasma levels, while SE was negatively associated with cortisol plasma levels in women (all p 0.027). Sleep quality is not related to levels of plasma anabolic hormones, but to levels of catabolic hormones, in sedentary middle-aged adults. Therefore, these results suggest that potential changes in aging biomarkers associated with sleep disturbances, could be mediated by age-related changes in the catabolic endocrine system

Validity of four commercially available metabolic carts for assessing resting metabolic rate and respiratory exchange ratio in nonventilated humans

Supported by the Spanish Ministry of Economy and Competitiveness via Retos de la Sociedad grant DEP2016-79512-R (to JRR), and European Regional Development Fund (ERDF); Spanish Ministry of Education grant (FPU15/04059 to JMAA; FPU19/01609 to LJF; and FPU18/03357 to MD-M); the University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (to JRR) -Plan Propio de Investigacion 2018 Programa Contratos-Puente and Programa Perfeccionamiento de Doctores (to GS-D); Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades grant SOMM17/6107/UGR (to JRR) via the ERDF; and the Fundacion Alfonso Martin Escudero (to GS-D); Funding for open access charge: Universidad de Granada/CBUA.Background & aims: The validity of most commercially available metabolic cart is mostly unknown. Thus, we aimed to determine the accuracy, precision, within-subject reproducibility, and concordance of RMR and RER measured by four commercially available metabolic carts [Cosmed Q-NRG, Vyaire Vyntus CPX, Maastricht Instruments Omnical, and Medgraphics Ultima CardiO2]. Further, we studied whether a previously proposed simulation-based post-calorimetric calibration of cart readouts [individual calibration control evaluation (ICcE)] modify the RMR and RER reproducibility and concordance. Methods: Three experiments simulating different RMR and RER by controlled pure gas (N-2 and CO2) infusions were conducted on 5 non-consecutive days. Moreover, 30-min methanol burns were performed on 3 non-consecutive days. Lastly, the RMR and RER of 29 young non-ventilated adults (11 women; 25 +/- 4 years-old; BMI: 24.1 +/- 3.2 kg/m(2)) were assessed twice using each instrument, 24 hours apart, under standardized conditions. Results: The Omnical presented the lowest measurement error for RER (Omnical = 1.7 +/- 0.9%; Vyntus = 4.5 +/- 2.0%; Q-NRG = 6.6 +/- 1.9%; Ultima = 6.8 +/- 6.5%) and EE (Omnical = 1.5 +/- 0.5%; Q-NRG = 2.5 +/- 1.3%; Ultima = 10.7 +/- 11.0%; Vyntus = 13.8 +/- 5.0%) in all in vitro experiments (controlled pure gas infusions and methanol burns). In humans, the 4 metabolic carts provided discordant RMR and RER estimations (all P < 0.001). No differences were detected in RMR within-subject reproducibility (P = 0.058; Q-NRG inter-day coefficient of variance = 3.6 +/- 2.5%; Omnical = 4.8 +/- 3.5%; Vyntus = 5.0 +/- 5.6%; Ultima = 5.7 +/- 4.6%), although the Ultima CardiO2 provided larger RER inter-day differences (4.6 +/- 3.5%) than the others carts (P = 0.001; Omnical = 1.9 +/- 1.7%; Vyntus = 2.1 +/- 1.3%; Q-NRG = 2.4 +/- 2.1%). The ICcE procedure did not modify the RMR or RER concordance and did not reduce the inter-day differences in any of the carts. Conclusions: The 4 metabolic carts provided discordant measurements of RMR and RER. Overall, the Omnical provides more accurate and precise estimations of RMR and RER than the Q-NRG, Vyntus and Ultima CardiO(2), and might be considered the best for assessing RMR and RER in non-ventilated humans. Finally, our results do not support the use of an ICcE procedure.Spanish Ministry of Economy and Competitiveness via Retos de la Sociedad grant DEP2016-79512-REuropean Commission Spanish Government FPU15/04059 FPU19/01609 FPU18/03357University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and HealthPlan Propio de Investigacion 2018 Programa Contratos-Puente and Programa Perfeccionamiento de DoctoresJunta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades via the ERDF SOMM17/6107/UGRFundacion Alfonso Martin EscuderoUniversidad de Granada/CBU

Different exercise training modalities similarly improve heart rate variability in sedentary middle‑aged adults: the FIT‑AGEING randomized controlled trial

Funding for open access charge: Universidad de Granada/CBUA.Purpose This study aimed to investigate the influence of different exercise training modalities on heart rate variability (HRV) in sedentary middle-aged adults; and to study whether changes in health-related outcomes (i.e., body composition and cardiometabolic risk) are associated with those hypothetical HRV changes in sedentary middle-aged adults. Methods A total of 66 middle-aged adults (53.6 ± 4.4 years old; 50% women) were enrolled in the FIT-AGEING study. We conducted a 12-week randomized controlled trial. The participants were randomly assigned to 4 groups: (a) a control group (no exercise); (b) a physical activity recommendation from the World Health Organization group (PAR); (c) a high-intensity interval training group (HIIT); and (d) a high-intensity interval training group adding whole-body electromyostimulation (HIIT + EMS). Results All exercise training modalities induced changes in HRV parameters (all P ≤ 0.001) without statistical differences between them (all P > 0.05). We found associations between changes in body composition and cardiometabolic risk and exercise-related changes in HRV. Conclusion Our results suggest that different exercise interventions (i.e., PAR, HIIT and HIIT + EMS) induced an enhancement of HRV in sedentary middle-aged adults. Our findings support the notion that exercise-related changes in HRV are associated with changes in body composition and cardiometabolic risk after the intervention programUniversidad de Granada/CBU

Association between Sleep Quality and Body Composition in Sedentary Middle-Aged Adults

Background: Ageing is associated with sleep pattern changes and body composition changes, which are related to several diseases. Purpose: This study aimed to analyse the association between sleep quality and an extensive set of body composition parameters (waist-hip ratio, body mass index, bone mineral content, bone mineral density, lean mass, lean mass index, fat mass, fat mass percentage, fat mass index, visceral adipose tissue) and sleep quality in sedentary middle-aged adults. We also aimed to evaluate whether the possible associations accord between subjective and objective measurements of sleep quality. Methods: 74 (39 women) middle-aged sedentary adults (40–65 years old) participated in the present study. The sleep quality was assessed using the Pittsburgh sleep quality index (PSQI) scale and accelerometers. A PSQI global score more than 5 indicates poor sleep quality. Weight, height, waist and hip circumferences were measured, and body mass index and waist-hip ratio were also calculated. Body composition was assessed with a dual-energy X-ray absorptiometry scanner. Results: The PSQI global score was negatively associated with bone mineral content, bone mineral density, lean mass, lean mass index and positively associated with fat mass percentage. No association was found between accelerometer parameters and body composition variables. Conclusion: We showed that a subjective poor sleep quality was negatively associated with bone mineral content (BMC), bone mineral density (BMD), lean mass and lean mass index (LMI) whereas was positively associated with fat mass percentage in middle-aged adults. We also observed that these associations did not accord with objective sleep quality measurements

Association of meal timing with body composition and cardiometabolic risk factors in young adults

Purpose To investigate the association of meal timing with body composition and cardiometabolic risk factors in young adults. Methods In this cross-sectional study participated 118 young adults (82 women; 22 ± 2 years old; BMI: 25.1 ± 4.6 kg/m2). Meal timing was determined via three non-consecutive 24-h dietary recalls. Sleep outcomes were objectively assessed using accelerometry. The eating window (time between first and last caloric intake), caloric midpoint (local time at which ≥ 50% of daily calories are consumed), eating jetlag (variability of the eating midpoint between non-working and working days), time from the midsleep point to first food intake, and time from last food intake to midsleep point were calculated. Body composition was determined by DXA. Blood pressure and fasting cardiometabolic risk factors (i.e., triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and insulin resistance) were measured. Results Meal timing was not associated with body composition (p > 0.05). The eating window was negatively related to HOMA-IR and cardiometabolic risk score in men (R2 = 0.348, β = − 0.605; R2 = 0.234, β = − 0.508; all p ≤ 0.003). The time from midsleep point to first food intake was positively related to HOMA-IR and cardiometabolic risk score in men (R2 = 0.212, β = 0.485; R2 = 0.228, β = 0.502; all p = 0.003). These associations remained after adjusting for confounders and multiplicity (all p ≤ 0.011). Conclusions Meal timing seems unrelated to body composition in young adults. However, a longer daily eating window and a shorter time from midsleep point to first food intake (i.e., earlier first food intake in a 24 h cycle) are associated with better cardiometabolic health in young men. Clinical trial registration NCT0236512

Impact of methods for data selection on the day-to-day reproducibility of resting metabolic rate assessed with four different metabolic carts

Background and aims: Accomplishing a high day-to-day reproducibility is important to detect changes in resting metabolic rate (RMR) and respiratory exchange ratio (RER) that may be produced after an intervention or for monitoring patients’ metabolism over time. We aimed to analyze: (i) the influence of different methods for selecting indirect calorimetry data on RMR and RER assessments; and, (ii) whether these methods influence RMR and RER day-to-day reproducibility. Methods and results: Twenty-eight young adults accomplished 4 consecutive RMR assessments (30-min each), using the Q-NRG (Cosmed, Rome, Italy), the Vyntus CPX (Jaeger-CareFusion, Höchberg, Germany), the Omnical (Maastricht Instruments, Maastricht, The Netherlands), and the Ultima CardiO2 (Medgraphics Corporation, St. Paul, Minnesota, USA) carts, on 2 consecutive mornings. Three types of methods were used: (i) short (periods of 5 consecutive minutes; 6e10, 11e15, 16e20, 21e25, and 26e30 min) and long time intervals (TI) methods (6e25 and 6 e30 min); (ii) steady state (SSt methods); and, (iii) methods filtering the data by thresholding from the mean RMR (filtering methods). RMR and RER were similar when using different methods (except RMR for the Vyntus and RER for the Q-NRG). Conversely, using different methods impacted RMR (all P 0.037) and/or RER (P 0.009) day-to-day reproducibility in all carts. The 6e25 min and the 6e30 min long TI methods yielded more reproducible measurements for all metabolic carts. Conclusion: The 6e25 min and 6e30 min should be the preferred methods for selecting data, as they result in the highest day-to-day reproducibility of RMR and RER assessments.This work was supported by the Spanish Ministry of Economy and Competitiveness via Retos de la Sociedad grant DEP2016-79512-R (to JRR), and European Regional Development Funds (ERDF); Spanish Ministry of Education grant (FPU15/04059 to JMAA; FPU19/01609 to LJ-F; and FPU18/03357 to MD-M); the University of Granada Plan Propio de Investigación 2016-Excellence actions: Unit of Excellence on Exercise and Health (to JRR); the University of Granada Plan Propio 2020 and 2018 Programa Contratos-Puente (to JMA and GS-D, respectively), and Programa Perfeccionamiento de Doctores (to GS-D); Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades grant SOMM17/6107/UGR (to JRR) via the ERDF; Grant FJC2020-044453-I funded by MCIN/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR” (to JMA); the Fundación Alfonso Martín Escudero (to GS-D); and a Marie Skłodowska-Curie Actions-Individual Fellowship grant (Horizon2020, 101028941, to GS-D)

Acute Effects of Whole-Body Electromyostimulation on Energy Expenditure at Resting and during Uphill Walking in Healthy Young Men

The effects of the different electrical frequencies of whole-body electrical stimulation (WB-EMS) on energy expenditure (EE) and the respiratory exchange ratio (RER) remain poorly understood. This study aimed to determine the effects of different WB-EMS electrical frequencies on EE and the RER during supine resting and uphill walking. A total of 10 healthy and recreationally active men (21.6 +/- 3.3 years old) participated in the present study. Participants completed two testing sessions in a randomized order. In each session, a variety of impulse frequencies (1 hertz (Hz), 2 Hz, 4 Hz, 6 Hz, 8 Hz, and 10 Hz) were applied in a randomized order, allowing a 10 min passive recovery between them. Oxygen consumption and carbon dioxide production were measured to calculate EE and the RER. All frequencies increased EE at rest (all p = 0.923). During uphill walking, the frequency that elicited the highest increase in EE was 6 Hz (Delta = 4.87 +/- 0.84 kcal/min) compared to the unstimulated condition. None of the impulse frequencies altered the RER during uphill walking. WB-EMS increases EE in healthy young men both during resting and uphill walking.WiemsPro S.L.University of GranadaUnit of Excellence on Exercise and Health (UCEES)Plan Propio de Investigacion 2016, Excellence actions: Units of Excellenc

Cuando comer: investigando el rol del horario de las comidas y del ayuno intermitente en la composición corporal y la salud cardiometabólica en humanos

Meal timing and intermittent fasting have emerged as potential dietary interventions for managing obesity. However, their impact on human health is still not fully comprehended. The objectives of the present International Doctoral Thesis are to summarize the effects of various types of intermittent fasting on body composition and cardiometabolic health in humans, with a particular emphasis on energy metabolism (Chapter 1). Additionally, the thesis aims to explore the relationship between meal timing with body composition and cardiometabolic risk factors in young men and women (Chapter 4). Furthermore, it seeks to assess the efficacy of three different 8-hour time-restricted eating schedules (early, late and selfselected vs. usual-care) on visceral adipose tissue, body composition and cardiometabolic health in men and women with overweight/obesity and slight metabolic impairments (Chapter 5). The results of this thesis suggest that meal timing is not cross-sectionally associated with body composition in young men and women. However, it was observed that a longer daily eating window and a shorter time from midsleep point to first food intake (i.e., earlier first food intake in a 24-hour cycle) are associated with better cardiometabolic health in young men (Chapter 4). The thesis also highlights that self-selected time-restricted eating (TRE) may be an effective strategy for reducing visceral adipose tissue in men. Additionally, implementing an 8-hour TRE, regardless of the timing of the eating window, as part of a usual-care intervention without specific energy restriction resulted in greater body weight loss in both men and women, although no differences between intervention groups were observed in the changes in body composition or cardiometabolic risk factors. It is noteworthy that weight loss exceeding a clinically meaningful threshold (≥5%) was observed in some individuals, leading to improvements in cardiometabolic health (Chapter 5). Based on the findings of this International Doctoral Thesis, an 8-hour TRE can be considered a simple strategy for clinicians to teach their patients during routine care. It leads to greater body weight loss compared to a usual-care intervention.El horario de las comidas y el ayuno intermitente han surgido como posibles intervenciones dietéticas para el tratamiento de la obesidad. Sin embargo, su impacto en la salud humana aún no se comprende completamente. Los objetivos de esta Tesis Doctoral Internacional son resumir los efectos de varios tipos de ayuno intermitente en la composición corporal y la salud cardiometabólica en humanos, con un énfasis particular en el metabolismo energético (Capítulo 1). Además, explora la relación entre el horario de las comidas y la composición corporal y los factores de riesgo cardiometabólico en hombres y mujeres jóvenes (Capítulo 4). Asimismo, evalúa la eficacia de tres esquemas diferentes de 8 horas de restricción de la ingesta nutricional (temprano, tardía, autoseleccionado vs. tratamiento habitual) en el tejido adiposo visceral, la composición corporal y la salud cardiometabólica en hombres y mujeres con sobrepeso/obesidad y leves alteraciones metabólicas (Capítulo 5). Los resultados de esta tesis sugieren que el horario de las comidas no está asociado transversalmente con la composición corporal en jóvenes. Sin embargo, una ventana de alimentación más prolongada y un tiempo más corto desde el punto medio del sueño hasta la primera ingesta de alimentos (es decir, una primera ingesta de alimentos más temprana en un ciclo de 24 horas) están relacionados con una mejor salud cardiometabólica en hombres (Capítulo 4). La tesis destaca que un esquema autoseleccionado de restricción temporal de la ingesta nutricional puede ser una estrategia efectiva para reducir el tejido adiposo visceral en hombres. Además, implementar una restricción temporal de 8 horas de la ingesta nutricional, independientemente del momento del día, como parte de una intervención estándar sin restricción específica de energía, resultó en una mayor pérdida de peso corporal tanto en hombres como en mujeres. No se observaron diferencias entre los grupos de intervención en los cambios en la composición corporal o los factores de riesgo cardiometabólico. Se observó una pérdida de peso que superó un umbral clínicamente relevante (≥5%) en algunos individuos, lo cual condujo a mejoras en la salud cardiometabólica (Capítulo 5). Basándose en los hallazgos de esta Tesis Doctoral Internacional, una restricción temporal de 8 horas de la ingesta nutricional puede considerarse una estrategia sencilla a implementar en atención primaria y produce a una mayor pérdida de peso corporal que una intervención estándar.Tesis Univ. Granada.Formación de Profesorado Universitario (FPU18/03357) del Ministerio de Ciencia, Innovación y Universidades (actualmente Ministerio de Universidades)Secretaría de Estado de Universidades, Investigación, Desarrollo e Innovación (BOE-B-2018- 48361, publicado el 9 de octubre de 2018)Spanish Ministry of Economy and Competitiveness (PTA 12264), Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI13/01393).Retos de la Sociedad (DEP2016-79512-R), Fondos Estructurales de la Unión Europea (FEDER).Spanish Ministry of Universities (FPU 13/04365, 14/04172, 15/04059, 16/05159, 16/028028, and 17/01523).Fundación Iberoamericana de Nutrición (FINUT).Redes temáticas de investigación cooperativa RETIC (Red SAMID RD16/0022).AstraZeneca HealthCare Foundation.University of Granada, Plan Propio de Investigación 2016 and 2017, Excellence actions: Units of Excellence; Unit of Excellence on Exercise Nutrition and Health (UCEENS) and Plan Propio de Investigación 2018 and 2019 Programa Contratos-Puente and Plan Propio de Investigación 2018 Programa Perfeccionamiento de Doctores.Junta de Andalucía, Conserjería de Conocimiento, Investigación y Universidades (ERDF: ref. SOMM17/6107/UGR).Danone Institute. Ref. Danone 2017.Fundación Alonso Martín Escudero.Junta de Andalucía, Consejería de Transformación económica, Industria, Conocimiento y Universidades (A-CTS-516-UGR20).University of Granada, Plan Propio de Investigación 2022, Excellence actions: Units of Excellence; Unit of Excellence on Exercise Nutrition and Health (UCEENS), 2022-2023- Research contract; and Junta de Andalucía y Fondo Europeo de Desarrollo Regional (FEDER).Juan de la Cierva Formación (FJC-2020-043385-I and FJC2020-044453-I) funded by the Ministerio de Ciencia e Innovación and by the European Union NextGenerationEU/PRTR.Recualification of the Spanish University System 2021-2023 from the Spanish Ministry of Universities (RD 289/2021), funded by the European Union-NextGenerationEU.The Government of Navarra, Departamento de Desarrollo Economico y Empresarial (0011-1365-2021-000000), Plan de Promoción de Grupos de Investigación.Margarita Salas grant (RCMS-22-KIAO1C-24-GSMTDX) funded by Ministerio de Ciencia e Innovación and by the European Union NextGenerationEU/RRF.Spanish Ministry of Universities (FPU 18/03357 and 21/01161)