Physical exercise: a polypill against chronic kidney disease.

We are currently facing a pandemic of physical inactivity that might contribute to the growing prevalence of chronic kidney disease (CKD). Here, we summarize currently available evidence on the association between physical activity and CKD, and also review the effects of exercise intervention in affected patients. Physical activity/exercise might act as a polypill against CKD, preventing its development or even exerting beneficial effects once it is established (i.e. improvements in patients' physical fitness and cardiovascular risk, as well as in kidney function). Exercise benefits are also found at advanced CKD stages or in patients under hemodialysis. The biological mechanisms behind the clinical evidence are also discussed. An active lifestyle appears as a cornerstone in CKD prevention and management.

Lifestyle and cardiovascular risk in working young adults: insights from a nationwide Spanish cohort.

INTRODUCTION AND OBJECTIVES: This study aimed to describe the cardiovascular risk profile of working young adults from Spain and its association with lifestyle. METHODS: Participants (18-30 years) were recruited from a nationwide cohort of economically active adults insured by a large occupational risk prevention company, with data obtained from routine medical assessments. The participants were categorized as having an "unhealthy" cardiovascular risk profile based on the presence of prediabetes/diabetes, prehypertension/hypertension, or hypercholesterolemia, or a "healthy" profile if these conditions were completely absent. The association with lifestyle factors (weight, physical activity, sleeping characteristics, alcohol consumption, smoking) was assessed. RESULTS: A total of 78 421 young adults (27±2 years, 36% female) were evaluated at baseline. The "unhealthy" cardiovascular risk profile was prevalent (18%) and inversely associated (OR, 0.64; 95%CI, 0.57-0.80) with an optimal lifestyle (normal weight, regular physical activity, no drinking/smoking, and good sleep). The latter condition was found in only 3.5% of the participants. On the other hand, prospective analyses in 44 776 participants (median follow-up=2 [range 2-5] years) showed that 2.0% transitioned from a "healthy" to an "unhealthy" profile. Being physically active (OR, 0.95; 95%CI, 0.81-0.99) and having a normal weight (OR, 0.61; 95%CI, 0.51-0.70) were associated with a lower likelihood of this transition. No consistent associations were found for other lifestyle factors. CONCLUSIONS: The prevalence of cardiovascular risk factors is high in economically active young Spanish adults. An unhealthy cardiovascular risk profile is inversely associated with an optimal lifestyle, but the latter is highly infrequent in this population.

Physical activity, chronic kidney disease, and cardiovascular risk: A study in half a million adults.

OBJECTIVE: There is a growing prevalence of chronic kidney disease (CKD), a condition associated with a higher cardiovascular disease (CVD) risk. We assessed the association between self-reported physical activity (PA) and CKD and also studied whether PA attenuates CKD-associated CVD risk. METHODS: A cohort of Spanish adults (18-64 years) participated in this nationwide study. Participants were categorized at baseline as being either inactive (performing no PA), regularly, or insufficiently active (meeting or not, respectively, international PA recommendations) and were followed for up to 5 years. The presence of CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2 ) and major CVD risk factors (diabetes, hypercholesterolemia, hypertension, obesity) was determined at baseline and at follow-up. RESULTS: 517 917 participants (44 ± 9 years, 67% male, CKD prevalence = 7%) were studied at baseline, with prospective analyses (median follow-up = 2 years, range = 2-5) in a subcohort of 264 581 individuals. Compared to physical inactivity, cross-sectional analyses at baseline showed that regular PA (odds ratio = 0.80; 95% confidence interval = 0.79-0.81), but not insufficient PA (1.02; 0.99-1.04) was associated with lower CKD prevalence. However, prospective analyses failed to confirm this association (p > 0.1). In turn, CKD was associated with a higher prevalence of hypertension (+3%) and diabetes (+5%) at baseline and with a greater incidence of hypertension at follow-up (+37%). Among those participants with CKD, regular PA was associated with a lower prevalence (-45% to -7%) and incidence (-38% to -4%) of all CVD risk factors. CONCLUSION: Although PA might not reduce incident CKD in the middle term (~2 years), it can attenuate the CVD risk linked to this condition.

Obesity, cardiovascular risk, and lifestyle: cross-sectional and prospective analyses in a nationwide Spanish cohort.

AIMS: To assess whether overweight and obesity are independently associated with cardiometabolic health [as categorized based on the presence/absence of cardiovascular disease (CVD) risk factors (diabetes, hypercholesterolaemia, or hypertension)], and the role of lifestyle on this association. METHODS AND RESULTS: A nationwide cohort of Spanish adults (18-64 years) was studied using a cross-sectional design and prospective observational design. Lifestyle-related factors (physical activity, sleeping characteristics, alcohol drinking, and smoking) were registered, and participants were classified as having an 'unhealthy' or 'healthy' cardiometabolic status attending to the presence or absence, respectively, of ≥1 CVD risk factor. A number of 596 111 participants (44 ± 9 years, 67% male) were studied at baseline, with prospective analyses in a subcohort [n = 302 061; median follow-up, 2 years (range, 2 to 5)]. Compared to normal weight, overweight and obesity were associated with a higher prevalence [odds ratio, 1.67 (95% confidence interval, 1.61-1.67) and 2.70 (2.69-2.78), respectively] and incidence [1.62 (1.59-1.67) and 2.70 (2.63-2.78)] of an unhealthy cardiometabolic status. Meeting physical activity guidelines reduced the odds of an unhealthy cardiometabolic status at baseline [0.87 (0.85-0.88)] among individuals with overweight/obesity, as well as of transitioning from a healthy status to an unhealthy status during the follow-up [0.87 (0.84-0.94)]. No significant associations were found for the remainder of lifestyle factors. CONCLUSION: Overweight and obesity are independently associated with an unhealthy cardiometabolic status. Regular physical activity attenuates not only the prevalence but also the incidence of CVD risk factors.

This study (n = 596 111, with 302 061 participants followed for ∼2 years) indicates that overweigh and obesity are independently associated with the prevalence and incidence of major cardiovascular disease (CVD) risk factors (hypertension, diabetes, and hypercholesterolaemia). Individuals with metabolically healthy overweight/obesity are more likely to develop CVD risk factors in the short-to-middle term than their peers with normal weight even after accounting for lifestyle. Regular physical activity is the only lifestyle factor that seems to be inversely and independently associated with the prevalence and incidence of the studied CVD risk factors among individuals with overweight/obesity.

Effects of physical exercise on physical function in older adults in residential care: a systematic review and network meta-analysis of randomised controlled trials.

BACKGROUND: Physical exercise is effective at attenuating ageing-related physical decline in general, but evidence of its benefits for older adults in residential care, who often have functional dependency, multimorbidity, and polypharmacy, is inconclusive. We aimed to establish the effects of exercise interventions on the physical function of this population. METHODS: For this systematic review and network meta-analysis, we searched PubMed, Web of Science, Cochrane Library, Rehabilitation & Sports Medicine Source, and SPORTDiscus to identify randomised controlled trials assessing the effects of exercise interventions (vs usual care) on physical function (ie, functional independence, physical performance, and other related measures, such as muscle strength, balance, or flexibility) in adults aged 60 years or older living in residential care. Relevant studies published in English or Spanish up to Jan 12, 2023, were included in the systematic review. The quality of studies was assessed using the Tool for the Assessment of Study Quality and Reporting in Exercise (TESTEX) score. A network meta-analysis was performed for physical function-related outcomes reported in at least ten studies, with subanalyses for specific intervention (ie, exercise type, training volume, and study duration) and participant (eg, having cognitive impairment or dementia, pre-frail or frail status, and being functionally dependent) characteristics. The study protocol was registered on PROSPERO (CRD42021247809). FINDINGS: 147 studies (11 609 participants, with mean ages ranging from 67 years [SD 9] to 92 years [2]) were included in the systematic review, and were rated as having overall good quality (median TESTEX score 9 [range 3-14]). In the meta-analysis (including 105 studies, n=7759 participants), exercise interventions were associated with significantly improved overall physical function, with a standardised mean difference [SMD] of 0·13 (95% credible interval [CrI] 0·04-0·21), which was confirmed in all analysed subpopulations. The strongest association was observed with 110-225 min per week of exercise, and the greatest improvements were observed with 170 min per week (SMD 0·36 [95% CrI 0·20-0·52]). No significant differences were found between exercise types. Subanalyses showed significant improvements for almost all analysed physical function-related outcomes (Barthel index, five-times sit-to-stand test, 30-s sit-to-stand test, knee extension, hand grip strength, bicep curl strength, Short Physical Performance Battery, 6-min walking test, walking speed, Berg balance scale, and sit-and-reach test). Large heterogeneity was found between and within studies in terms of population and intervention characteristics. INTERPRETATION: Exercise interventions are associated with improved physical function in older adults in residential care, and should, therefore, be routinely promoted in long-term care facilities. FUNDING: None. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Obesity and the risk of cardiometabolic diseases.

The prevalence of obesity has reached pandemic proportions, and now approximately 25% of adults in Westernized countries have obesity. Recognized as a major health concern, obesity is associated with multiple comorbidities, particularly cardiometabolic disorders. In this Review, we present obesity as an evolutionarily novel condition, summarize the epidemiological evidence on its detrimental cardiometabolic consequences and discuss the major mechanisms involved in the association between obesity and the risk of cardiometabolic diseases. We also examine the role of potential moderators of this association, with evidence for and against the so-called 'metabolically healthy obesity phenotype', the 'fatness but fitness' paradox or the 'obesity paradox'. Although maintenance of optimal cardiometabolic status should be a primary goal in individuals with obesity, losing body weight and, particularly, excess visceral adiposity seems to be necessary to minimize the risk of cardiometabolic diseases.

Association between self-reported sleep characteristics and cardiovascular risk factors: Weight status and physical activity matter.

We analysed the association between self-reported sleep characteristics and the prevalence of major cardiovascular disease (CVD) risk factors attending to the potential effect of physical activity (PA) and weight status. A large cohort of Spanish workers (n = 527,662; 32% female, 44 ± 9yrs) participated in this cross-sectional study. We assessed participants' self-reported indicators of sleep quantity (short [<6 h/d], normal [6-9 h/d] or long [>9 h/d]) and quality (unrestful or restful, and difficulties or not falling asleep) as well as the presence of major CVD risk factors (diabetes, hypertension and hypercholesterolemia); and categorised participants based on PA ("inactive", "insufficiently active" or "regularly active") and weight status (normal weight, overweight or obesity). Impairments in any sleep quantity or quality indicator, respectively, were significantly (p < 0.05) associated with the prevalence of at least one CVD risk factor. Yet, being physically active and having normal weight markedly attenuated these associations. Thus, individuals with poor sleep quantity or quality but who were physically active and had normal weight showed no different risk of hypertension or diabetes than those with normal sleep characteristics, albeit the former still presented a higher risk of hypercholesterolemia if they reported short sleep (+5% vs. normal duration, p = 0.047), unrestful sleep (+9% vs. restful, p < 0.001) or having difficulties to fall asleep (+48% vs. no difficulties, p < 0.001). The present findings support the need for maintaining optimal PA levels and weight status in order to minimise the CVD risk associated with poor sleep quantity or quality.HighlightsBoth sleep quantity and quality are associated with the prevalence of hypertension, diabetes, and hypercholesterolemia.Being physically active and having normal weight markedly reduces the cardiovascular risk associated with poor sleep quantity/quality.Having poor sleep quantity/quality while being also inactive and overweight/obese predisposes to a higher cardiovascular risk.

Normative Values for Sport-Specific Left Ventricular Dimensions and Exercise-Induced Cardiac Remodeling in Elite Spanish Male and Female Athletes.

BACKGROUND: There is debate about the magnitude of geometrical remodeling [i.e., left ventricle (LV) cavity enlargement vs. wall thickening] in the heart of elite athletes, and no limits of normality have been yet established for different sports. We aimed to determine sex- and sport-specific normative values of LV dimensions in elite white adult athletes. METHODS: This was a single-center, retrospective study of Spanish elite athletes. Athletes were grouped by sport and its relative dynamic/static component (Mitchell's classification). LV dimensions were measured with two-dimensional-guided M-mode echocardiography imaging to compute normative values. We also developed an online and app-based calculator ( https://sites.google.com/lapolart.es/athlete-lv/welcome?authuser=0 ) to provide clinicians with sports- and Mitchell's category-specific Z-scores for different LV dimensions. RESULTS: We studied 3282 athletes (46 different sports, 37.8% women, mean age 23 ± 6 years). The majority (85.4%) showed normal cardiac geometry, particularly women (90.9%). Eccentric hypertrophy was relatively prevalent (13.4%), and concentric remodeling or hypertrophy was a rare finding (each < 0.8% of total). The proportion of normal cardiac geometry and eccentric hypertrophy decreased and increased, respectively, with the dynamic (in both sexes) or static component (in male athletes) of the sport irrespective of the other (static or dynamic) component. The 95th percentile values of LV dimensions did not exceed the following limits in any of the Mitchell categories: septal wall thickness, 12 mm (males) and 10 mm (females); LV posterior wall, 11 mm and 10 mm; and LV end-diastolic diameter, 64 mm and 57 mm. CONCLUSIONS: The majority of elite athletes had normal LV geometry, and although some presented with LV eccentric hypertrophy, concentric remodeling or hypertrophy was very uncommon. The present study provides sport-specific normative values that can serve to identify those athletes for whom a detailed examination might be recommendable (i.e., those exceeding the 95th percentile for their sex and sport).

Strenuous Endurance Exercise and the Heart: Physiological versus Pathological Adaptations.

Although the benefits of regular physical activity on cardiovascular health are well established, the effects of strenuous endurance exercise (SEE) have been a matter of debate since ancient times. In this article, we aim to provide a balanced overview of what is known about SEE and the heart-from epidemiological evidence to recent cardiac imaging findings. Lifelong SEE is overall cardioprotective, with endurance master athletes showing in fact a youthful heart. Yet, some lines of research remain open, such as the need to elucidate the time-course and potential relevance of transient declines in heart function (or increases in biomarkers of cardiac injury) with SEE. The underlying mechanisms and clinical relevance of SEE-associated atrial fibrillation, myocardial fibrosis, or high coronary artery calcium scores also remain to be elucidated. © 2022 American Physiological Society. Compr Physiol 12:1-19, 2022.

Exercise Training and Natural Killer Cells in Cancer Survivors: Current Evidence and Research Gaps Based on a Systematic Review and Meta-analysis.

BACKGROUND: Exercise training can positively impact the immune system and particularly natural killer (NK) cells, at least in healthy people. This effect would be of relevance in the context of cancer given the prominent role of these cells in antitumor immunity. In this systematic review and meta-analysis, we aimed to summarize current evidence on the effects of exercise training on the levels and function of NK cells in cancer survivors (i.e., from the time of diagnosis until the end of life). METHODS: Relevant articles were searched in PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (until January 11, 2022). Randomized controlled trials (RCT) of exercise training (i.e., non-acute) interventions vs usual care conducted in cancer survivors and assessing NK number and/or cytotoxic activity (NKCA) before and upon completion of the intervention were included. Methodological quality of the studies was assessed with the PEDro scale, and results were meta-analyzed using a random effects (Dersimoian and Laird) model. RESULTS: Thirteen RCT including 459 participants (mean age ranging 11-63 years) met the inclusion criteria. Methodological quality of the studies was overall fair (median PEDro score = 5 out of 10). There was heterogeneity across studies regarding cancer types (breast cancer, non-small cell lung cancer and other solid tumors), treatment (e.g., receiving vs having received chemotherapy), exercise modes (aerobic or resistance exercise, Tai Chi, Yoga) and duration (2-24 weeks). No consistent effects were observed for NK number in blood (mean difference [MD]: 1.47, 95% confidence interval [CI] - 0.35 to 3.29, p = 0.113) or NKCA as assessed in vitro (MD: - 0.02, 95%CI - 0.17 to 0.14, p = 0.834). However, mixed results existed across studies, and some could not be meta-analyzed due to lack of information or methodological heterogeneity. CONCLUSIONS: Current evidence does not support a significant effect of exercise training intervention on NK cells in blood or on their 'static response' (as assessed in vitro) in cancer survivors. Several methodological issues and research gaps are highlighted in this review, which should be considered in future studies to draw definite conclusions on this topic.

Diabetes, Hypertension, and the Mediating Role of Lifestyle: A Cross-Sectional Analysis in a Large Cohort of Adults.

INTRODUCTION: Whether diabetes is associated with hypertension risk remains controversial, potentially owing to the confounding effect of lifestyle. This study aims to analyze the association between diabetes and hypertension in adults and the mediating impacts of lifestyle. METHODS: A cohort of Spanish workers (aged 18-64 years) insured by an occupational risk prevention company participated in this nationwide cross-sectional study between 2012 and 2016 (data analysis was performed in 2021). Participants' lifestyle‒related factors-BMI, sleeping hours, alcohol, smoking, and physical activity-were assessed, and the prevalence of hypertension and diabetes was registered. RESULTS: A total of 451,157 participants (33.1% women, aged 44.5 [SD=9.2] years, 3.2% with diabetes, and 29.3% with hypertension) with complete data for all variables were assessed. Having diabetes was associated with a higher prevalence of hypertension even after adjusting for all lifestyle-related factors (OR=1.44, 95% CI=1.43, 1.48), and people with diabetes and hypertension had a higher prevalence of mild kidney function impairment than people with diabetes alone (OR=1.06, 95% CI=1.01, 1.13). However, people with diabetes and an optimal lifestyle-normal weight and sleeping hours, absent-to-little alcohol drinking, nonsmoking, and regular physical activity-presented a prevalence of hypertension comparable with that of those without diabetes (OR=1.00, 95% CI=0.71, 1.32). In separate analyses among people with diabetes, an optimal lifestyle was associated with a lower prevalence of hypertension than the worse-opposite-lifestyle (OR=0.29, 95% CI=0.18, 0.53). The lifestyle-related factors showing the strongest inverse association with adjusted risk of hypertension were normal weight (OR=0.49, 95% CI=0.42, 0.53 versus overweight/obesity) and regular physical activity (OR=0.79, 95% CI=0.74, 0.82 versus inactivity). CONCLUSIONS: Diabetes is positively and largely independently associated with hypertension risk. Yet, a healthy lifestyle can attenuate this association.

Poor self-reported sleep is associated with risk factors for cardiovascular disease: A cross-sectional analysis in half a million adults.

BACKGROUND: Sleep is known to affect cardiovascular health, but some controversy exists on the independent association between different sleep characteristics (duration, restfulness, difficulties falling asleep) and specific risk factors for cardiovascular disease (CVD). We aimed to assess the association between self-reported sleep characteristics and the likelihood of major CVD risk factors. METHODS: Totally, 521,364 Spanish workers (32% female, 44 ± 9 years [18-64]) insured by an occupational risk prevention company participated in this nationwide cross-sectional study. Participants' sleep was considered 'poor' if they reported having ≥1 of the following conditions: excessively short (<6 h/d) or long (>9 h/d) sleep, unrestful sleep, or difficulties to fall asleep. We assessed the independent association between aforementioned sleep characteristics and the prevalence of hypertension, diabetes, hypercholesterolaemia, obesity and physical inactivity. RESULTS: Poor sleep (reported by 33% of participants) was associated with a higher likelihood of presenting all CVD risk factors individually, particularly physical inactivity (which prevalence was ~3-fold higher in the poor sleep group compared with participants reporting no sleep abnormality). In separate analyses, all the different sleep characteristics were associated with the likelihood of ≥2 CVD risk factors. Participants with optimal sleep, normal sleep duration, no difficulties falling sleep and restful sleep showed a lower total CVD risk score than their peers with poor sleep, short sleep duration, difficulties falling sleep and unrestful sleep, respectively (all p < .001). CONCLUSIONS: Poor sleep was associated with a higher likelihood of presenting major CVD risk factors. These findings might support the importance of monitoring and improving sleep patterns for primary CVD prevention.

Mortality Risk from Neurodegenerative Disease in Sports Associated with Repetitive Head Impacts: Preliminary Findings from a Systematic Review and Meta-Analysis.

BACKGROUND: Professional athletes seem to have a lower overall mortality risk than the general population, but controversy exists about whether athletes in sports associated with repetitive head impacts have a higher risk of mortality from neurodegenerative diseases. OBJECTIVE: We aimed to determine the risk of mortality from neurodegenerative diseases in sports associated with repeated head impacts compared with the general population or compared with athletes with no such exposure. METHODS: We conducted a systematic review with meta-analysis, systematically searching PubMed, Web of Science, Scopus, and SPORTDiscus (since inception to 14 May 2021) for studies comparing the risk of death from neurodegenerative disease in athletes participating in contact sports in which their heads recurrently receive blows from the bodies of other participants or from a ball versus a control group or dataset representing the general population. RESULTS: Six moderate- to high-quality retrospective studies including data from 41,699 athletes participating in contact sports (boxing, basketball, ice hockey, American Football and soccer) met all inclusion criteria to be included in the systematic review. Of these, three studies (N = 37,065 male professional soccer players) could be meta-analysed. Despite no differences in the risk of all-cause (p = 0.138), cardiovascular (p = 0.085) and cancer-related mortality (p = 0.136), soccer players presented with a significantly higher mortality risk from motor neuron disease (standard mortality rate 8.43; 95% confidence interval 3.07-23.13; p < 0.001). CONCLUSIONS: Although more research is needed (particularly in other contact sports and with neurodegenerative disease as the cause of death), preliminary evidence suggests that participation in professional soccer might increase the risk of mortality from motor neuron disease compared with the general population. The present findings highlight the need for the design of preventive measures and for adequate neuropsychological monitoring in these athletes. PROSPERO REGISTRATION: CRD42020195647.

Acute Aerobic Exercise Induces Short-Term Reductions in Ambulatory Blood Pressure in Patients With Hypertension: A Systematic Review and Meta-Analysis.

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Exercise interventions in Alzheimer's disease: A systematic review and meta-analysis of randomized controlled trials.

AIMS: To assess the potential multi-domain benefits of exercise interventions on patients with Alzheimer's disease (AD), as well as to determine the specific effects of different exercise modalities (aerobic, strength, or combined training). METHODS: A systematic search was conducted in PubMed and Web of Science until March 2021 for randomized controlled trials assessing the effect of exercise interventions (compared with no exercise) on patients with AD. Outcomes included cognitive function (mini-mental state examination [MMSE] test), physical function (e.g., 6-minute walking test [6MWT]), functional independence (Barthel index), and neuropsychiatric symptoms (Neuropsychiatric Inventory [NPI]). A random-effects meta-analysis was conducted. RESULTS: 28 studies (total n = 1337 participants, average age 79-90 years) were included in the systematic review, of which 21 could be meta-analyzed. Although considerable heterogeneity was found, exercise interventions induced several significant benefits, including in Barthel index (n = 147 patients, mean difference [MD]=8.36 points, 95% confidence interval [CI]=0.63-16.09), 6MWT (n = 369, MD=84 m, 95% CI=44-133)), and NPI (n = 263, MD=-4.4 points, 95% CI=-8.42 to -0.38). Benefits were also found in the MMSE test, albeit significance was only reached for aerobic exercise (n = 187, MD=2.31 points, 95% CI 0.45-4.27). CONCLUSIONS: Exercise interventions appear to exert multi-domain benefits in patients with AD.

Effects of Combining a Ketogenic Diet with Resistance Training on Body Composition, Strength, and Mechanical Power in Trained Individuals: A Narrative Review.

Ketogenic diets (KD) have gained popularity in recent years among strength-trained individuals. The present review summarizes current evidence-with a particular focus on randomized controlled trials-on the effects of KD on body composition and muscle performance (strength and power output) in strength-trained individuals. Although long-term studies (>12 weeks) are lacking, growing evidence supports the effectiveness of an ad libitum and energy-balanced KD for reducing total body and fat mass, at least in the short term. However, no or negligible benefits on body composition have been observed when comparing hypocaloric KD with conventional diets resulting in the same energy deficit. Moreover, some studies suggest that KD might impair resistance training-induced muscle hypertrophy, sometimes with concomitant decrements in muscle performance, at least when expressed in absolute units and not relative to total body mass (e.g., one-repetition maximum). KD might therefore be a beneficial strategy for promoting fat loss, although it might not be a recommendable option to gain muscle mass and strength/power. More research is needed on the adoption of strategies for avoiding the potentially detrimental effect of KD on muscle mass and strength/power (e.g., increasing protein intake, reintroduction of carbohydrates before competition). In summary, evidence is as yet scarce to support a major beneficial effect of KD on body composition or performance in strength-trained individuals. Furthermore, the long-term effectiveness and safety of this type of diet remains to be determined.

Anthropometric and fitness normative values for young karatekas.

To provide information regarding the anthropometric and fitness profile of young karatekas and to study its evolution with age. Data from top-level karatekas were included in the analysis: 97 athletes in the U14 category (12-13 years old), 238 in cadet (14-15 years old), 261 in junior (16-17 years old) and 177 in U21 (18-20 years old), which makes a total of 773 athlete data sets. Karatekas underwent anthropometric (weight, height, body mass index and body fat percentage) and fitness (sit and reach, 20-m shuttle run, standing long jump, overhead 3-kg ball throw, 10x5-m shuttle run, and plate-tapping) assessments during the training camps organized by the Spanish National Karate Federation between 1999 and 2016. Male karatekas were taller and heavier, and performed better than females in all the fitness dimensions assessed, except for flexibility and speed of upper limb movements. The obtained cardiovascular and lower-body muscular values indicated that karatekas in this study were placed between the 80th and the 90th percentile when compared with the general population. The results of the agility, coordination and speed of upper limb movements, and flexibility tests showed that the karatekas obtained much higher scores than those observed in age-matched populations. Young karatekas show a high fitness level in comparison with the general population, especially with regards to aerobic performance, lower-body muscular power and upper-limb movement speed. Reference values of anthropometric and fitness dimensions are provided in order to be used by coaches, conditioning trainers and sport scientists when testing young male and female karatekas.