Ardévol A, Adán C, Remesar X, Fernández-López J A, Alemany M
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, E-08028 Barcelona, Spain.
Pflugers Arch. 1998 Mar;435(4):454-64. doi: 10.1007/s004240050539.
To analyse the effect of obesity on exercise-derived heat dissipation, lean and obese Zucker rats were exercised on an inclined treadmill until they would no longer run with gentle prodding. We measured their oxygen consumption, water vapour loss, the concentrations of adenosine tri- and diphosphate, creatine phosphate, and lactate in quick-frozen leg muscles, and the temperature of muscle, skin and blood in the aorta. We determined blood flow to leg muscle, fat and skin by measuring the entrapment of fluorescent microspheres. From the measurements we calculated heat flow rates between hind leg muscle, blood, fat and skin and the environment. The obese rats weighed twice as much as the lean (340-400 g and 175-200 g respectively) and ran half as fast (113 +/- 7 m versus 257 +/- 17 m). The differences between the two groups for basal oxygen consumption (lean: 6.7 +/- 0.9 micromol/min, obese: 5.0 +/- 1.9 micromol/min) and exercising oxygen consumption (lean: 37.8 +/- 5.6 micromol/min, obese: 22.2 +/- 3.8 micromol/min) were not significant. Both groups stopped running after the same time at their maximal speed (lean: 4.5 +/- 0.3 min, obese: 4.2 +/- 0.2 min). During exercise, lean rats had higher increases in core temperature (lean: 0.7 degrees C, obese: 0.4 degrees C) and muscle temperatures (lean: 1.3 degrees C, obese: 0.7 degrees C) than the obese rats. The calculated heat flows indicated a predominant conductive transfer of heat from muscle through the skin in lean rats but a higher proportion of heat transfer to the blood in obese rats. It is concluded that muscle heat accumulation did not cause fatigue in either case.
为分析肥胖对运动产生的散热的影响，将瘦型和肥胖型 Zucker 大鼠置于倾斜的跑步机上运动，直至在轻轻刺激下它们不再跑动。我们测量了它们的耗氧量、水汽损失、速冻腿部肌肉中三磷酸腺苷、二磷酸腺苷、磷酸肌酸和乳酸的浓度，以及肌肉、皮肤和主动脉血液的温度。通过测量荧光微球的滞留情况，我们测定了腿部肌肉、脂肪和皮肤的血流量。根据这些测量结果，我们计算了后腿肌肉、血液、脂肪、皮肤与环境之间的热流率。肥胖大鼠的体重是瘦型大鼠的两倍（分别为 340 - 400 克和 175 - 200 克），奔跑速度则为瘦型大鼠的一半（113 ± 7 米对 257 ± 17 米）。两组之间基础耗氧量（瘦型：6.7 ± 0.9 微摩尔/分钟，肥胖型：5.0 ± 1.9 微摩尔/分钟）和运动耗氧量（瘦型：37.8 ± 5.6 微摩尔/分钟，肥胖型：22.2 ± 3.8 微摩尔/分钟）的差异不显著。两组在以各自最大速度奔跑相同时间后停止（瘦型：4.5 ± 0.3 分钟，肥胖型：4.2 ± 0.2 分钟）。运动期间，瘦型大鼠的核心体温（瘦型：0.7℃，肥胖型：0.4℃）和肌肉温度（瘦型：1.3℃，肥胖型：0.7℃）升高幅度高于肥胖大鼠。计算得出的热流表明，瘦型大鼠中热量主要通过皮肤从肌肉传导传递，但肥胖大鼠中热量传递至血液的比例更高。结论是，在两种情况下肌肉热量积累均未导致疲劳。
