Physical fitness is independently related to blood leptin concentration and insulin sensitivity index in male subjects with central adiposity

Cardiorespiratory fitness and the relationship between body fat and resting testosterone in men

Objective: To examine the effect of cardiovascular fitness, i.e. VO₂max, on the relationship between weight status and resting testosterone level (RTL) in males.Materials and methods: A subset of male participants from the 2003-2004 National Health and Nutrition Examination Survey were analyzed by weight status, i.e. normal, overweight, obese, and all participants. Bivariate correlation coefficients were computed for RTL, percent body fat (BF%), and VO₂max. Partial correlation coefficients were computed between RTL and BF% controlling for VO₂max and between RTL and VO₂max controlling for BF%.Results: Bivariate correlations between RTL and BF%, and RTL and VO₂max were significant in all groups. The partial correlation coefficients between RTL and BF% controlling for VO₂max were significant in the normal and all participants group. When RTL and VO₂max were analyzed controlling for BF% only the all participants group remained significant.Conclusion: Cardiovascular fitness or weight status may independently influence RTL in males.

In middle-aged and old obese patients, training intervention reduces leptin level: A meta-analysis

BACKGROUND

Leptin is one of the major adipokines in obesity that indicates the severity of fat accumulation. It is also an important etiological factor of consequent cardiometabolic and autoimmune disorders. Aging has been demonstrated to aggravate obesity and to induce leptin resistance and hyperleptinemia. Hyperleptinemia, on the other hand, may promote the development of age-related abnormalities. While major weight loss has been demonstrated to ameliorate hyperleptinemia, obese people show a poor tendency to achieve lasting success in this field. The question arises whether training intervention per se is able to reduce the level of this adipokine.

OBJECTIVES

We aimed to review the literature on the effects of training intervention on peripheral leptin level in obesity during aging, in order to evaluate the independent efficacy of this method. In the studies that were included in our analysis, changes of adiponectin levels (when present) were also evaluated.

DATA SOURCES

3481 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 19 articles were suitable for analyses.

STUDY ELIGIBILITY CRITERIA

Empirical research papers were eligible provided that they reported data of middle-aged or older (above 45 years of age) overweight or obese (body mass index above 25) individuals and included physical training intervention or at least fitness status of groups together with corresponding blood leptin values.

STATISTICAL METHODS

We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. To assess publication bias Egger's test was applied. In case of significant publication bias, the Duval and Tweedie's trim and fill algorithm was used.

RESULTS

Training intervention leads to a decrease in leptin level of middle-aged or older, overweight or obese male and female groups, even without major weight loss, indicated by unchanged serum adiponectin levels. Resistance training appears to be more efficient in reducing blood leptin level than aerobic training alone.

CONCLUSIONS

Physical training, especially resistance training successfully reduces hyperleptinemia even without diet or major weight loss.

Testosterone and Adipokines are Determinants of Physical Performance, Strength, and Aerobic Fitness in Frail, Obese, Older Adults

In this study, we evaluated the independent and combined effects of baseline circulating gonadal, anabolic hormones and adipokines on physical function in 107 frail, obese (BMI ≥ 30 kg/m(2)), and older (≥65 yr) subjects. Our results showed significant positive correlations between circulating testosterone and insulin growth factor-1 (IGF-1) with knee flexion, knee extension, one-repetition maximum (1-RM), and peak oxygen consumption (VO2 peak), while no correlation was observed with estradiol. Among the adipokines, high sensitivity C-reactive protein (Hs-CRP) and leptin negatively correlated with the modified physical performance testing (PPT), knee flexion, knee extension, 1-RM, and VO2 peak. Interleukin-6 ( Il-6) negatively correlated with knee flexion and VO2 peak and soluble tumor necrosis factors receptor-1 (sTNFr1) correlated with PPT, 1-RM, and VO2 peak. Adiponectin correlated negatively with 1-RM. Multiple regression analysis revealed that, for PPT, sTNFr1 was the only independent predictor. Independent predictors included adiponectin, leptin, and testosterone for knee flexion; leptin and testosterone for knee extension; adiponectin, leptin, and testosterone for 1-RM; and IGF-1, IL-6, leptin, and testosterone for VO2 peak. In conclusion, in frail obese older adults, circulating levels of testosterone, adiponectin, and leptin appear to be important predictors of physical strength and fitness, while inflammation appears to be a major determinant of physical frailty.