Relationships of multifunctional hormone leptin with anthropometry, aerobic capacity and physical activity in peripubertal boys
Date
2014-07-07
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Abstract
Rasvkoe ainevahetuse uuringutes peetakse üheks peamiseks hormooniks leptiini määramist. Leptiin on otseselt seotud rasvkoe kaaluga. Käesoleva uuringu eesmärgiks oli uurida seoseid vere leptiinisisalduse ning nahavoltide paksuse, ümbermõõtude, maksimaalse hapnikutarbimise võime ning kehalise aktiivsuse vahel erineva kehamassi indeksiga (KMI) puberteediealistel poistel. Kokku uuriti 248 10-12 aastast poissi, kes esimeses ja teises uuringus jagati kolme gruppi KMI järgi (normaalkaal, ülekaalus ja rasvunud). Kolmandas uuringus, kus uuriti kehaliselt aktiivseid normaalse KMI poisse, jaotati gruppidesse vastavalt vere leptiinisisaldusele - keskmine, madal ja kõrge. Meie uuringus mõõdeti 9 nahavoltide paksust ning 13 ümbermõõtu. Nahavoldi paksused olid usutavalt seotud leptiiniga kogugrupis, normaalse KMI ning ülekaaluliste grupis. Nii kogugrupis kui ka normaalse KMI grupis on 9 nahavoldi summa eelkõige seotud vere leptiinisisaldusega. Ümbermõõdud ei ole otseselt seotud vere leptiinisisaldusega rasvunute grupis. Selgus, et lihtsa küsimustiku abil määratud kehalise aktiivsuse näitajad poistel, kellel on normaalne KMI kuid väga erinev vere leptiinisisaldus on ainult mõõduka intensiivsusega kehaline aktiivsus seotud leptiiniga ja seda ainult kõrge leptiinisisaldusega grupis. Meie uuringus leiti negatiivne seos leptiini ja suhtelise hapnikutarbimise vahel. Seega suure aeroobse võimekusega poistel, kellel on oletatavasti vähe rasvkudet on ka madal vere leptiinisisaldus.
Leptin has a permissive role in high energy metabolic processes occurring during puberty. The task of this dissertation is to study possible relationships between leptin, skinfold thicknesses (9) and circumferences (13), peak oxygen consumption, and different levels of physical activity in peripubertal boys with different body mass indices (BMI). As a subjects 248 10-to- 12- year old boys in the first and second study were divided into three BMI subgroups (normal weight, overweight and obese). In the third study boys with normal BMI were selected to the three groups according to leptin levels - average, low and high. Our study confirms that all measured skinfold thicknesses correlate significantly with leptin in all subgroups. In the total and normal BMI groups, the sum of skinfolds is the best parameter to characterize leptin concentration. Circumferences are not the best parameters that characterize body fat mass in the obese group and for this reason no significant correlations with leptin emerged. In our study we used a simple questionnaire for measuring physical activity of different intensity and duration. We studied a subgroups of boys with normal, high and low leptin. In these groups the correlation between leptin and physical activity was weak. Significant correlation emerged only between leptin and regular moderate aerobic physical activity in high leptin subgroup. In our study we found negative correlation between leptin and relative peak oxygen consumption (per kg body weight) in all subgroups.
Leptin has a permissive role in high energy metabolic processes occurring during puberty. The task of this dissertation is to study possible relationships between leptin, skinfold thicknesses (9) and circumferences (13), peak oxygen consumption, and different levels of physical activity in peripubertal boys with different body mass indices (BMI). As a subjects 248 10-to- 12- year old boys in the first and second study were divided into three BMI subgroups (normal weight, overweight and obese). In the third study boys with normal BMI were selected to the three groups according to leptin levels - average, low and high. Our study confirms that all measured skinfold thicknesses correlate significantly with leptin in all subgroups. In the total and normal BMI groups, the sum of skinfolds is the best parameter to characterize leptin concentration. Circumferences are not the best parameters that characterize body fat mass in the obese group and for this reason no significant correlations with leptin emerged. In our study we used a simple questionnaire for measuring physical activity of different intensity and duration. We studied a subgroups of boys with normal, high and low leptin. In these groups the correlation between leptin and physical activity was weak. Significant correlation emerged only between leptin and regular moderate aerobic physical activity in high leptin subgroup. In our study we found negative correlation between leptin and relative peak oxygen consumption (per kg body weight) in all subgroups.
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Keywords
leptiin, antropomeetria, kehaline töövõime, füüsiline aktiivsus, poisid, murdeiga, leptin, anthropometry, physical work capacity, physical activity, boys, puberty