Cardiorespiratory fitness (CRF) is positively associated with insulin sensitivity, whereas excessive levels of visceral adipose tissue (AT) and liver fat (LF) are both associated with insulin resistance and impaired plasma glucose/insulin homeostasis. To what extent levels of visceral AT and LF content contribute to the relationship between CRF and indices of plasma glucose/insulin homeostasis is uncertain. Our objective was to explore the interactions between CRF, visceral AT and LF with glucose tolerance/insulin levels in asymptomatic and apparently healthy individuals. CRF was measured in 135 women and 177 men with a maximal treadmill graded exercise test. Indices of plasma glucose/insulin homeostasis were derived from a 3-hour oral glucose tolerance test (OGTT) performed in the morning after a 12-hour fast. Visceral AT levels and LF content were measured using magnetic resonance imaging and spectroscopy. For any given CRF level, women presented significantly lower visceral AT and LF than men as well as lower HOMA-IR and plasma glucose/insulin levels during the OGTT compared to men. In both sexes, there were significant negative correlations between CRF and HOMA-IR as well as glucose and insulin levels measured during the OGTT. Both glucose and insulin levels during the OGTT correlated positively with visceral AT and LF. In women and men, being in the top CRF tertile was associated with low levels of visceral AT and LF. Multivariable linear regression analyses suggested that visceral AT and LF were plausible mediators of the association between CRF and indices of plasma glucose/insulin homeostasis.

中文翻译：

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内脏脂肪和肝脂肪是心肺适应性与血浆葡萄糖-胰岛素稳态之间联系的中介。

心脏呼吸适应度（CRF）与胰岛素敏感性呈正相关，而内脏脂肪组织（AT）和肝脂肪（LF）过量与胰岛素抵抗和血浆葡萄糖/胰岛素体内稳态受损有关。内脏AT和LF含量在多大程度上有助于CRF与血浆葡萄糖/胰岛素稳态指数之间的关系，尚不确定。我们的目标是探讨无症状和显然健康个体中CRF，内脏AT和LF与葡萄糖耐量/胰岛素水平之间的相互作用。在最大的跑步机分级运动测试中，对135名女性和177名男性进行了CRF测量。血浆葡萄糖/胰岛素稳态的指标来自禁食12小时后于早晨进行的3小时口服葡萄糖耐量测试（OGTT）。使用磁共振成像和光谱法测量内脏AT水平和LF含量。对于任何给定的CRF水平，与男性相比，女性在OGTT期间内脏的AT和LF明显低于男性，并且HOMA-IR和血浆葡萄糖/胰岛素水平也较低。在男女中，CRF和HOMA-IR以及OGTT期间测得的葡萄糖和胰岛素水平之间均存在显着的负相关。OGTT期间的葡萄糖和胰岛素水平与内脏AT和LF呈正相关。在男性和女性中，处于最高的CRF三分位与内脏AT和LF含量低有关。多变量线性回归分析表明，内脏AT和LF是CRF与血浆葡萄糖/胰岛素稳态指数之间关联的合理媒介。