Vallerand A L, Jacobs I
Environmental Physiology Section, Defence and Civil Institute of Environmental Medicine, North York, Ontario, Canada.
Metabolism. 1990 Nov;39(11):1211-8. doi: 10.1016/0026-0495(90)90097-v.
Recent human studies have shown that cold exposure increases lipid oxidation, even when the oxidation of circulating free fatty acid (FFA) is markedly reduced by the ingestion of nicotinic acid, thus seriously questioning the importance of FFA for lipid oxidation in the cold-exposed humans. It was therefore hypothesized that similarly to prolonged exercise, fatty acids from plasma triglycerides (TG) are important energy substrates for oxidation during prolonged cold exposure in man. The goal of this study was to determine the influence of cold exposure on an index of plasma TG utilization, the intravenous fat tolerance test (IVFTT). To evaluate the possibility of a delayed increase in fat tolerance, a second cold exposure and an IVFTT were also performed 24 hours after the first cold exposure. Seven healthy males (fasting, seminude) were subjected to an IVFTT (1 mL/kg 10% Intralipid) on three occasions while resting for 160 minutes: (1) at 29 degrees C, (2) in the cold (10 degrees C, 1 m/s wind), and (3) at 10 degrees C 24 hours after the first cold test. One week separated the warm test from the cold tests. Cold exposure reduced mean body temperature by 3.4 +/- 0.1 degree C and increased energy expenditure 2.5 times in comparison to warm values (P less than .01). It also increased fat oxidation by 70% (P less than .05) and plasma glycerol levels (P less than .05), but did not alter fat tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)
近期的人体研究表明，即使摄入烟酸会显著降低循环游离脂肪酸（FFA）的氧化，冷暴露仍会增加脂质氧化，这严重质疑了FFA在冷暴露人体脂质氧化中的重要性。因此，有人提出假设，与长时间运动类似，血浆甘油三酯（TG）中的脂肪酸是人体长时间冷暴露期间氧化的重要能量底物。本研究的目的是确定冷暴露对血浆TG利用指标——静脉脂肪耐量试验（IVFTT）的影响。为了评估脂肪耐量延迟增加的可能性，在第一次冷暴露24小时后还进行了第二次冷暴露和IVFTT。七名健康男性（空腹、半裸）在休息160分钟的情况下，分三次进行IVFTT（1 mL/kg 10%英脱利匹特）：（1）在29摄氏度时，（2）在寒冷环境中（10摄氏度，风速1米/秒），以及（3）在第一次冷试验后24小时于10摄氏度时进行。温暖试验与冷试验间隔一周。与温暖环境下的值相比，冷暴露使平均体温降低了3.4±0.1摄氏度，能量消耗增加了2.5倍（P<0.01）。它还使脂肪氧化增加了70%（P<0.05）以及血浆甘油水平升高（P<0.05），但未改变脂肪耐量。（摘要截选至250词）
