Jonatan Ruiz

University of Granada | UGR · Departamento de Educación Física y Deportiva

The standard method for identifying active Brown Adipose Tissue (BAT) is [¹⁸F]-Fluorodeoxyglucose ([¹⁸F]-FDG) PET/CT imaging, which is costly and exposes patients to radiation, making it impractical for population studies. These issues can be addressed with computational methods that predict [¹⁸F]-FDG uptake by BAT from CT; earlier population studi...

Predictive equations are widely employed for estimating the volume of oxygen consumption (VO2) while walking, which is ultimately employed to determine energy expenditure and tailor exercise prescription. This study aimed to test the agreement between the measured VO2 and estimated VO2 during a walking protocol on a treadmill at 3.5, 4.5, 5.5, and...

Background Sarcopenia and low areal bone mineral density (aBMD) are prevalent musculoskeletal complications after paediatric cancer treatment. However, their relationship has not been examined in young paediatric cancers survivors. This study aimed to evaluate aBMD differences according to sarcopenia status and the risk of low aBMD Z‐score in young...

Context Exercise reduces adiposity, but its influence on bone marrow fat fraction (BMFF) is unknown; nor is it known whether a reduction in liver fat content mediates this reduction. Objectives This work aimed to determine whether incorporating exercise into a lifestyle program reduces the lumbar spine (LS) BMFF and to investigate whether changes...

Stroke is the leading cause of disability and the second cause of death worldwide. The increasing burden of stroke underscores the importance of optimising rehabilitation protocols. Virtual reality (VR) can improve poststroke prognosis. A VR software combining gamification, full immersion and stroke specificity (ie, the Development and validation o...

Background Handgrip strength has been related with multiple health outcomes, including all-cause mortality and morbidity. Handgrip testing is a highly valid and reliable method, included in evidence-based fitness test batteries from preschool to older ages. Previously, Jamar and TKK dynamometers have shown good reliability and validity against know...

Objective Moderate‐to‐vigorous physical activity (MVPA) improves glucose levels; however, whether its timing affects daily glycemic control remains unclear. This study aims to investigate the impact of lifestyle MVPA timing on daily glycemic control in sedentary adults with overweight/obesity and metabolic impairments. Methods A total of 186 adult...

10070 Background: Required treatments to cure pediatric cancer at such a young age increase the risk of later health-related complications. Early exposure to DNA damaging agents, during a vital period of active skeletal growth, interferes with accrual of bone mass. Treatments not only impair bone health, but also affect skeletal muscle function and...

BACKGROUND While surgery is commonly regarded as the primary curative treatment for colorectal cancer, it could potentially be associated with postoperative morbidity and mortality. OBJECTIVE Determining the pooled effect of exercise and multidisciplinary prehabilitation interventions on postoperative hospital length of stay and functional capacit...

Surveillance of health-related physical fitness can improve decision-making and intervention strategies promoting health for children and adolescents. However, no study has comprehensively analyzed surveillance/monitoring systems for physical fitness globally. This review sought to address this gap by identifying: (1) national-level surveillance/mo...

Purpose We aimed to examine the associations of 24-hour movement behaviors (moderate-to-vigorous physical activity [MVPA], light physical activity [LPA], sedentary behavior [SB] and sleep) with age-, sex- and race-specific areal bone mineral density (aBMD) Z-score parameters at clinical sites in young pediatric cancer survivors. Methods This cross...

Objective To determine differences in resting heart rate variability (HRV) and heart rate (HR) between young adults with normal‐weight obesity (NWO) and normal‐weight lean (NWL). Methods A total of 65 normal‐weight individuals (18–25 years old, 50 women, body mass index 18.5 to 24.9 kg/m ² ) were included in this cross‐sectional study. Body fat pe...

Introduction Metabolic dysfunction-associated steatotic liver disease is a major public health problem considering its high prevalence and its strong association with extrahepatic diseases. Implementing strategies based on an intermittent fasting approach and supervised exercise may mitigate the risks. This study aims to investigate the effects of...

Objective The study objective was to investigate the effect of cold exposure on the plasma levels of five potential human brown adipokines (chemokine ligand 14 [CXCL14], growth differentiation factor 15 [GDF15], fibroblast growth factor 21 [FGF21], interleukin 6 [IL6], and bone morphogenic protein 8b [BMP8b]) and to study whether such cold‐induced...

Cold exposure activates brown adipose tissue (BAT) and potentially improves cardiometabolic health through the secretion of signaling lipids by BAT. Here, we show that 2 h of cold exposure in young adults increases the levels of omega-6 and omega-3 oxylipins, the endocannabinoids (eCBs) anandamide and docosahexaenoylethanolamine, and lysophospholip...

Background Pediatric cancer survivors are at increased risk of muscle weakness and low areal bone mineral density (aBMD). However, the prevalence of muscle strength deficits is not well documented, and the associations of muscle strength with aBMD are unknown in this population. Therefore, this study aimed to investigate the prevalence of upper- an...

Background There is a subset of individuals with overweight/obesity characterized by a lower risk of cardiometabolic complications, the so-called metabolically healthy overweight/obesity (MHOO) phenotype. Despite the relatively higher levels of subcutaneous adipose tissue and lower visceral adipose tissue observed in individuals with MHOO than indi...

Vitamin D deficiency is related to metabolic disturbances. Indeed, a poor vitamin D status has been usually detected in patients with cardiovascular disease (CVD). However, the relationship between vitamin D and CVD risk factors in young adults remains controversial at present. This study aimed to examine the association between circulating 25-hydr...

Background and aim: The endocannabinoid system is a signalling system composed of endocannabinoids (eCBs), their receptors, and the enzymes involved in their synthesis and metabolism. Alterations in the ECS are linked to the development of cardiometabolic diseases. Here, we investigated the relationship between plasma levels of eCBs and their anal...

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 trai...

The present study aimed to investigate the effect of a 24-week aerobic + resistance training programs at moderate versus vigorous intensity on body composition, and the persistence of the changes after a 10-month free-living period, in young untrained adults. This report is based on a secondary analysis from the activating brown adipose tissue thro...

Background: Hepatic disorders are often complex and multifactorial, modulated by genetic and environmental determinants. During the last years, the hepatic disease has been progressively established from early stages in life. The use of genetic risk scores (GRS) to predict the genetic susceptibility to a particular phenotype among youth has gained...

We investigated the interaction between a genetic score and an exercise intervention on brain health in children with overweight/obesity. One hundred one children with overweight/obesity (10.0 ± 1.5 years, 59% girls) were randomized into a 20-week combined exercise intervention or a control group. Several cognitive and academic outcomes were measur...

Aim Previous evidence suggest that a sexual dimorphism in exercise fat oxidation and adipokines levels may explain a lower risk of cardio-metabolic disorders in women. Therefore, we investigated the role of sex in the relationship between adipokines levels, maximal fat oxidation (MFO) during exercise and insulin resistance. Methods Fifty young adu...

The objective of this longitudinal study was to analyze changes in physical activity, sedentary time, sleep, anxiety, mood, and perceived health as a result of COVID-19 pandemic in a cohort of Spanish university students, both during the home confinement and one year after. Additionally, we analyzed the associations between physical activity, seden...

Capsinoids may exert ergogenic effects on resistance exercises. However, the acute effects of capsinoids on neuromuscular performance in humans are unknown. Here, we aimed to investigate the acute effects of dihydrocapsiate on lower- and upper-body neuromuscular performance parameters in resistance-trained individuals. 25 young adults (n=6 women; a...

Neck adipose tissue (NAT) accumulation and neck circumference are independent predictors of cardiometabolic risk (CMR) and low-grade chronic inflammation in young adults. The present study examines whether a 24-week concurrent exercise intervention can reduce NAT volume and neck circumference in young adults, and whether any changes in these variab...

Importance: Childhood obesity is a risk factor associated with type 2 diabetes, cardiovascular disease, and mental disorders later in life. Investigation of the parallel effects of a defined exercise program on cardiometabolic and mental health in children with overweight or obesity may provide new insights on the potential benefits of exercise on...

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 calo...

Objective: Impaired daily functioning and psychiatric symptoms are highly prevalent in obstructive sleep apnea (OSA); however, the effects of weight loss and lifestyle interventions on these symptoms remain uncertain. This study aimed to evaluate the efficacy of an interdisciplinary weight loss and lifestyle intervention on impaired functioning, ps...

Circulating bile acids (BA) are signaling molecules that control glucose and lipid metabolism. However, the effects of acute exercise on plasma levels of BA in humans remain poorly understood. Here, we evaluate the effects of a bout of maximal endurance exercise (EE) and resistance exercise (RE) on plasma levels of BA in young, sedentary adults. Co...

Background Gut bacteria play a crucial role in the metabolism of bile acids (BA). Whether an association exists between the fecal microbiota composition and circulating BA levels in humans is poorly understood. Here, we investigated the relationship between fecal microbiota diversity and composition with plasma levels of BA in young adults. Method...

Background: Bone health is remarkably affected by endocrine side effects due to paediatric cancer treatments and the disease itself. We aimed to provide novel insights into the contribution of independent predictors of bone health in young paediatric cancer survivors. Methods: This cross-sectional multicentre study was carried out within the iBo...

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 objecti...

Background: Although regular physical activity and exercise programs might improve bone health caused by oncological treatment and the disease itself, it remains unknown the pooled effect of exercise interventions following frequency, intensity, time and type prescriptions. Objective: This systematic review and meta-analysis aimed to synthesise evi...

Objectives: To compare the effect of a single bout of morning vs. evening exercise on cardiovascular risk factors in adults. Design: Systematic review and meta-analysis. Methods: A systematic search of studies was conducted using PubMed and Web of Science from inception to June 2022. Selected studies accomplished the following criteria: crosso...

Objectives: (1) To develop reference values for health-related fitness in European children and adolescents aged 6–18 years that are the foundation for the web based, open-access and multi-language fitness platform (FitBack); (2) To provide comparisons across European countries. Methods: This study builds on a previous large fitness reference stud...

Background: Prior evidence suggests that capsinoids ingestion may increase resting energy expenditure (EE) and fat oxidation (FATox), yet whether they can modulate those parameters during exercise conditions remains poorly understood. We hypothesized that dihydrocapsiate (DHC) ingestion would increase EE and specifically FATox during an acute bout...

Importance Excess abdominal fat is a major determinant in the development of insulin resistance and other metabolic disorders. Increased visceral adipose tissue (VAT) seems to precede the development of insulin resistance and is therefore a prime target of childhood lifestyle interventions aimed at preventing diabetes. Objectives To examine the ef...

Pre-clinical studies suggest that circulating oxylipins, i.e., the oxidation products of polyunsaturated fatty acids (PUFAs), modulate gut microbiota composition in mice, but there is no information available in humans. Therefore, this study aimed to investigate the relationship between omega-3 and omega-6 derived oxylipins plasma levels and fecal...

Background Moderate altitudes carry physiological and metabolic changes that can dampen exercise performance. Fortunately, these changes can be modulated by an optimal nutritional intervention. This case study represents the first nutritional intervention of a moderate altitude athlete. These results may help to establish well-designed nutritional...

Background: To study the associations of Protein Tyrosine Phosphatase-N1 (PTPN1) polymorphisms with obesity-related phenotypes in European adolescents, and the influence of physical activity on these relationships. Methods: Five polymorphisms of PTPN1 were genotyped in 1057 European adolescents (12-18 years old). We measured several phenotypes r...

ONCOFIT is a randomized clinical trial with a two-arm parallel design aimed at determining the influence of a multidisciplinary Prehabilitation and Postoperative Program (PPP) on post-surgery complications in patients undergoing resection of colon cancer. This intervention will include supervised physical exercise, dietary behavior change, and psyc...

Background To study the associations of Protein Tyrosine Phosphatase-N1 (PTPN1) polymorphisms with obesity-related phenotypes in European adolescents, and the influence of physical activity on these relationships. Methods Five polymorphisms of PTPN1 were genotyped in 1,057 European adolescents (12–18 years old). We measured several phenotypes rela...

Background Fatty acid-derived lipid mediators including oxylipins, endocannabinoids (eCBs), and their analogues, have emerged as key metabolites in the inflammatory and immune response to physiological stressors. Methods This report was based on a sub-study and secondary analyses the ACTIBATE single-center unblinded randomized controlled trial (Cl...

Objective: Human brown adipose tissue (BAT) has gained considerable attention as a potential therapeutic target for obesity and its related cardiometabolic diseases; however, whether the gut microbiota might be an efficient stimulus to activate BAT metabolism remains to be ascertained. We aimed to investigate the association of fecal microbiota co...

Background Histone lactylation has been recently described as a novel histone post-translational modification linking cellular metabolism to epigenetic regulation. Results Given the expected relevance of this modification and current limited knowledge of its function, we generate genome-wide datasets of H3K18la distribution in various in vitro and...

RESUMEN La evaluación de la condición física en jóvenes es importante desde el punto de vista educativo, deportivo y la salud. El proyecto FitBack, financiado por la Comisión Europea, ha desarrollado una herramienta que permite interpretar los resultados de la evaluación de la condición física en niños/as y adolescentes de forma individualizada. El...

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 randomized controlled trial (ClinicalTrials.gov ID: NCT02365129) was therefore conducted to study the effects of a 24-week supervised exercise interventio...

Importance: Pediatric overweight and obesity are highly prevalent across the world, with implications for poorer cognitive and brain health. Exercise might potentially attenuate these adverse consequences. Objectives: To investigate the effects of an exercise program on brain health indicators, including intelligence, executive function, academi...

Purpose Metabolic flexibility (MetF), which is a surrogate of metabolic health, can be assessed by the change in the respiratory exchange ratio (RER) in response to an oral glucose tolerance test (OGTT). We aimed to determine the day-to-day reproducibility of the energy expenditure (EE) and RER response to an OGTT, and whether a simulation-based po...

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...

OBJECTIVE In adults, there is evidence that improvement of metabolic-associated fatty liver disease (MAFLD) depends on the reduction of myosteatosis. In children, in whom the prevalence of MAFLD is alarming, this muscle-liver crosstalk has not been tested. Therefore, we aimed to explore whether the effects of a multicomponent intervention on hepati...

Importance: Childhood obesity is a risk factor for type 2 diabetes (T2D), cardiovascular disease, and mental disorders later in life. To investigate the parallel effects on cardiometabolic and mental health in children with overweight or obesity will provide new insights on the benefits of exercise on overall health. Objective: This study aimed to...

Objectives Brown adipose tissue (BAT) is important in the maintenance of cardiometabolic health in rodents. Recent reports appear to suggest the same in humans, although if this is true remains elusive partly because of the methodological bias that affected previous research. This cross-sectional work reports the relationships of cold-induced BAT v...

This study investigated the effects of an eight-week interdisciplinary weight loss and lifestyle intervention on dietary behavior in men who were overweight/had obesity and moderate-to-severe obstructive sleep apnea (OSA). It was based on data from INTERAPNEA (ClinicalTrials.gov ID: NCT03851653); a randomized clinical trial conducted from April 201...

Objectives (1) To develop reference values for health-related fitness European children and adolescents aged 6–18 years that are the foundation for the web-based, open-access and multi-language fitness platform (FitBack); (2) To provide comparisons across European countries. Methods This study builds on a previous large fitness reference study in...

Purpose Brown adipose tissue (BAT) increases metabolic heat production in response to cold exposure. Body size and composition are involved in the human cold response, yet the influence of BAT herein have not fully been explored. Here, we aimed to study the association of the cold-induced shivering threshold time with body composition, BAT, the per...

Objective: To investigate the association of plasma levels of endocannabinoids with fecal microbiota. Methods: Plasma levels of endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), as well as their eleven analogues, and arachidonic acid (AA), were measured using liquid chromatography-tandem mass spectrometry in 92 young adults....

Aim To study the acute effect of a dietary multi-ingredient nootropic on cognitive performance in young healthy adults. We also analyzed the influence of the dietary multi-ingredient nootropic on emotional state, heart rate (HR), and heart rate variability (HRV). Methods This is a randomized, triple-blinded, placebo-controlled, crossover trial. In...

Brown adipose tissue (BAT) is a promising therapeutic target against obesity. Therefore, research on the genetic architecture of BAT could be key for the development of successful therapies against this complex phenotype. Hypothesis-driven candidate gene association studies are useful for studying genetic determinants of complex traits, but they ar...

Background and Aims This study aims to examine associations of food portion sizes (PS) with markers of insulin resistance (IR) and clustered of metabolic risk score in European adolescents. Methods 495 adolescents (53.5% females) from the HELENA study were included. The association between PS from food groups and HOMA-IR index, VO2 max, and metabo...