José Luis Mesa

Cardiorespiratory Fitness and Sedentary Activities Are Associated with Adiposity in Adolescents

Objective: To determine whether physical activity, sedentary activities, and/or cardiorespiratory fitness are related to waist circumference in adolescents, as previously reported in adults.

El perfil lipídico-metabólico en los adolescentes está más influido por la condición física que por la actividad física (estudio AVENA)*

Introduction and objectives. To determine whether the level of physical activity or physical fitness (i.e., aerobic capacity and muscle strength) in Spanish adolescents influences lipid and metabolic profiles. Methods. From a total of 2859 Spanish adolescents (age 13.0-18.5 years) taking part in the Diet and Appraisal of Nutrition State in Adolescents 460 (248 male, 212 female) were randomly selected for blood analysis. Their level of physical activity was determined by questionnaire. Aerobic capacity was assessed using the Course-Navette test. Muscle strength was evaluated using flexed arm. A lipidmetabolic cardiovascular risk index was derived from the levels of triglycerides, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and glucose. Results. No relationship was found between the level of physical activity and lipid‐metabolic index in either sex. In contrast, there was an inverse relationship between the lipid‐metabolic index and aerobic capacity in males (P=.003) after adjustment for physical activity level and muscle strength. In females, a favorable lipid‐metabolic index was associated with greater muscle strength (P=.048) after adjustment for aerobic capacity.

Oral Creatine Supplementation and Skeletal Muscle Metabolism in Physical Exercise

Creatine is the object of growing interest in the scientific literature. This is because of the widespread use of creatine by athletes, on the one hand, and to some promising results regarding its therapeutic potential in neuromuscular disease on the other. In fact, since the late 1900s, many studies have examined the effects of creatine supplementation on exercise performance. This article reviews the literature on creatine supplementation as an ergogenic aid, including some basic aspects relating to its metabolism, pharmacokinetics and side effects. The use of creatine supplements to increase muscle creatine content above ~20 mmol/kg dry muscle mass leads to improvements in high-intensity, intermittent high-intensity and even endurance exercise (mainly in nonweightbearing endurance activities). An effective supplementation scheme is a dosage of 20 g/day for 4–6 days, and 5 g/day thereafter. Based on recent pharmacokinetic data, new regimens of creatine supplementation could be used. Although there are opinion statements suggesting that creatine supplementation may be implicated in carcinogenesis, data to prove this effect are lacking, and indeed, several studies showing anticarcinogenic effects of creatine and its analogues have been published. There is a shortage of scientific evidence concerning the adverse effects following creatine supplementation in healthy individuals even with long-term dosage. Therefore, creatine may be considered as a widespread, effective and safe ergogenic aid.

The importance of cardiorespiratory fitness for healthy metabolic traits in children and adolescents: the AVENA Study

The protective effect of physical activity on total mortality, life expectancy, cardiovascular disease and diabetes has been widely reported in people of all ages (Strong et al. 2005; Jonker et al. 2006; Franco et al. 2005). Recent estimates suggest that obesity and physical inactivity are responsible for 400,000 deaths annually in the United States; thus, it is close to overtaking tobacco as the leading cause of preventable death (Mokdad et al. 2004). Cardiorespiratory fitness is a direct marker of physiological status and recent data suggest that fitness is one of the strongest predictors of health outcomes (Myers et al. 2002; Mora et al. 2003). In fact, cardiorespiratory fitness is a direct measure of physiological performance and of the ability to adapt to physical stress. Physical activity and cardiorespiratory fitness are closely related in that fitness is partially determined by physical activity patterns over recent weeks or months. Cardiorespiratory fitness is also determined by constitutional factors. It has been suggested that ~40% of variation in cardiorespiratory fitness is attributable to genetic factors (Bouchard 1986). Low cardiorespiratory fitness may threaten, together with the present obesity epidemic, to shorten life expectancy over the next few decades (Olshansky et al. 2005). Therefore, cardiorespiratory fitness has been suggested to be included in the European Health Monitoring System for the adult population (Sjöström et al. 2005). Ruiz et al. (2006) suggested that cardiorespiratory fitness should also be included in the health monitoring systems from the early stages of life. The results from the Swedish and Estonian part of the European Youth Heart Study (EYHS) revealed negative associations between cardiorespiratory fitness and features of metabolic syndrome in girls and boys aged 9–10 years (Ruiz et al. 2006). The findings are in concordance with a number of recent cross-sectional and prospective cohort studies elegantly summarized in the manuscript. They suggest that high cardiorespiratory fitness is associated with a healthier metabolic profile in children and adolescents and that high cardiorespiratory fitness during these stages of life seems to provide more health protection in adulthood. Similar results have been observed in a representative sample of Spanish adolescents participating in the “Alimentación y Valoración del Estado Nutricional de los Adolescentes” (AVENA) study (Gonzalez-Gross et al. 2003a; Moreno et al. 2003). The AVENA study is a population-based cross-sectional survey conducted in five different geographic areas of Spain, addressing genetic and environmental factors in relation to metabolic traits during adolescence. Some interesting data regarding cardiorespiratory fitness and cardiovascular risk factors are being obtained from this study. First findings from the AVENA pilot study revealed a negative association between body fat derived from the sum of four skinfolds and cardiorespiratory fitness in both boys and girls aged 13–18.5 years (Gonzalez-Gross et al. 2003b). After analyzing the total sample of participants (n=2859; 1357 boys, 1502 girls) we found that moderate to high levels of cardiorespiratory fitness were associated with lower abdominal adiposity (as measured by waist circumference) in both genders (Ortega et al. unpublished data). This association remained after adjustment for age, pubertal J. L. Mesa (*) . F. B. Ortega . J. R. Ruiz . M. J. Castillo . Á. Gutiérrez Department of Physiology, School of Medicine, University of Granada, Granada, Spain e-mail: jose.mesa@ems.rmit.edu.au Tel.: +34-958-243540 Fax: +34-958-249015

Anthropometric determinants of a clustering of lipid-related metabolic risk factors in overweight and non-overweight adolescents--influence of cardiorespiratory fitness. The Avena study.

Background/Aims: To explore in adolescents the associations between simple anthropometric variables with a continuously distributed summary score for lipid-related metabolic risk in both overweight and non-overweight adolescents, and to test whether these associations are modified by the level of cardiorespiratory fitness. Methods: Cardiorespiratory fitness, BMI, skinfold thicknesses, body circumferences, and a continuously distributed clustering of lipid- related metabolic risk (calculated from LDL and HDL choles- terol, triglycerides, and glucose) were measured in 524 adolescents (265 males, 259 females, 15.3 ± 1.4 years) from the cross-sectional multicentric AVENA study. Participants were classified as overweight (including obesity) or non-overweight. Results: Most anthropometric parameters were univariately related to the continuous lipid-related metabolic risk. However, after multicollinear analysis and generalized linear modelling, suprailiac skinfold thickness in males (p < 0.001, explained variance 12.2%) and waist-to-height ratio in females (p < 0.001, explained variance 10.0%) were the best determinants of the continuous metabolic risk score, after adjustment for age, sexual maturation, and economic status. These associations were slightly weakened in overweight males (p = 0.034) and females (p = 0.087), and did not interact with cardiorespiratory fitness. Conclusion: Our data emphasize the usefulness of suprailiac skinfold thickness in males and waist-to-height ratio in females as simple anthropometric measurements associated to an overall lipid-related metabolic risk, mainly in non-overweight adolescents and regardless their cardiorespiratory status.

Sports Requiring Stressful Physical Exertion Cause Abnormalities in Plasma Lipid Profile

OBJECTIVES To study the effect of different types of sports on plasma lipid profile. Subjects and method. Fasting plasma levels of total, LDL- and HDL-cholesterol (TC, LDLc, HDLc), triglycerides, phospholipids, apo A-I, apo B-100, and Lp(a) were measured in 28 swimmers, 17 volleyball players and 23 soccer players, and in a control group. All subjects participated in official national competitions except the control group. The results were compared to those in a control group of 26 healthy sedentary subjects. All groups were matched according to age, body mass index and nutritional status. Cutoff points to classify subjects with high plasma concentrations of Lp(a) and LDLc were 32 mg/dL and 128 mg/dL, respectively. For other variables the cutoff points were the third quartile values recorded in the control group, except for apo A-I and HDLc, for which we used the first quartile values. RESULTS Persons who practice sports involving a high level of physical exertion (volleyball and soccer players) had a less favorable lipid profile compared to control subjects. In contrast, swimmers had a more favorable lipid profile. The odds ratio for lipid profile anomalies was significantly higher in volleyball and soccer players, and lower in swimmers. In the former two groups we observed a clear tendency toward simultaneous elevations in LDLc, apo B-100 and Lp(a). In contrast, the opposite interaction was seen in swimmers, who had lower values for all lipids. CONCLUSION Our results show that stressful physical exertion can lead to abnormalities in plasma lipid profile.

Acknowledgement to the 2006 Reviewers

K. Gong, Yangzhou, China M. Greksak, Ivanka pri Dunaji, Slovenia S. Gupta, Baroda, India K. Haas, Berne, Switzerland P. Haber, Vienna, Austria E. Haddad, Loma Linda, Calif., USA D. Haffner, Rostock, Germany A. Hahn, Hannover, Germany M.H. Hamdaoui, Tunis, Tunisia L.J. Harvey, Norwich, USA M.H. Hirata, Sao Paulo, Brazil P. Holvoet, Leuven, Belgium C.Y. Hsu, Taiwan, ROC N. Hwalla, Beirut, Lebanon C.S. Johnston, Mesa, Ariz., USA J. Kaur, Chandigarh, India D.S. Kelley, Calif., USA M. Kilic, Konya, Turkey D. Kitts, Vancouver, B.C., Canada S. Knasmüller, Vienna, Austria K. Kobayashi-Hattori, Tokyo, Japan W. Kong, Shenyang, China M. Kornsteiner, Vienna, Austria M. Krawinkel, Giessen, Germany A. Kurpad, Bangalore, India H.N. Lafeber, The Netherlands A. Lau, Pittsburgh, Pa., USA R. Lemmens, Vienna, Austria Y. Levy, Haifa, Israel E. Lien, Adelaide, Australia J. Linseisen, Heidelberg, Germany H.C. Lo, Changhua, Taiwan, ROC J.J. Loor, Blacksburg, USA A. MacDonald, Birmingham, UK M.C. Mancini, Sao Paulo, Brazil M. Martin, Los Angeles, Calif., USA C. Menzaghi, San Giovanni Rotondo, Italy A. Misra, New Delhi, India B. Mittendorfer, Mo., USA O.M. Abdel-Salam, Cairo, Egypt K. Adeli, Ont., Canada L. Agius, Newcastle, UK V.G. Athyros, Thessaloniki, Greece F. Azizi, Tehran, Iran D. Bagchi, Omaha, Nebr., USA A.K. Baltaci, Konya, Turkey G. Barba, Rome, Italy M. Barile, Bari, Italy J. Beltowski, Lublin, Poland E. Benefice, La Paz, Bolivia S. Bengmark, London, UK I.F. Benter, Safat, Kuwait G. Bona, Novara, Italy J.M.E. Bourre, Paris, France G. Brabant, Hannover, Germany V.B. Brændholt, Copenhagen, Denmark L. Bretillon, Dijon, France P. Burckhardt, Lausanne, Switzerland P.C. Calder, Southampton, UK A. Cetinkaya, Kahramanmaras, Turkey J.M. Chardigny, Dijon, France S.H. Chen, Taiwan, ROC F. Chiarelli, Chieti, Italy F.T. Crews, USA Y. Cui, Bronx, N.Y., USA D. de Luis, Simancas, Spain M. Desai, Calif., USA H.H. Ditschuneit, Ulm, Germany W. Druml, Vienna, Austria M.A. Ergun, Besevler, Turkey P. Fasching, Vienna, Austria A. Flynn, Cork, Ireland J. Fontaine, Montreal, Que., Canada J.A. Foran, Milwaukee, Wisc., USA D. Genser, Vienna, Austria P. Ghafourifar, Ohio, USA K. Ghebremeskel, London, UK H. Goldenberg, Vienna, Austria