Jansson E
Acta Physiol Scand. 1982 Jan;114(1):103-10. doi: 10.1111/j.1748-1716.1982.tb06958.x.
Total respiratory exchange ratio (R) was compared to the respiratory exchange ratio over the legs (RQL) during exercise after different diets, to evaluate if R (which represents a mean for the whole body) can be used to estimate the relative proportions of fat and carbohydrate oxidation in exercising muscle. One important prerequisite for this is a steady state acid base balance, 7 subjects were studied at rest and during the later part of a 25 min exercise (65% of Vo2 max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake, R and arterial-femoral venous differences for [O2], [CO2], PCO2 and pH and arterial concentrations for lactate and beta-hydroxybutyrate were measured. Respiratory exchange ratio over the exercising legs (RQL) and ventilation/oxygen uptake were calculated. Arterial pH, PCO2, lactate and beta-hydroxybutyrate as well as specific ventilation attained steady levels during the later part of exercise after both diets. Although arterial lactate and beta-hydroxybutyrate differed between the diets, the arterial pH and specific ventilation were the same. Both R and RQL were higher after the carbohydrate than after the fat diet and there was no systematic difference between R and RQL. Therefore, it seems likely that R estimates the proportion of fat and carbohydrate oxidation in skeletal muscle during submaximal exercise after extreme diets.
在不同饮食后运动期间，将总呼吸交换率（R）与腿部呼吸交换率（RQL）进行比较，以评估R（代表全身的平均值）是否可用于估计运动肌肉中脂肪和碳水化合物氧化的相对比例。对此的一个重要前提是酸碱平衡处于稳定状态。7名受试者在两次实验中，分别在休息时以及25分钟运动（最大摄氧量的65%）后期接受了研究，第一次实验前采用富含脂肪的饮食，第二次实验前采用富含碳水化合物的饮食。测量了氧气摄取量、R以及动脉血与股静脉血之间[O₂] [CO₂]、PCO₂和pH的差异，以及乳酸和β-羟基丁酸的动脉血浓度。计算了运动腿部的呼吸交换率（RQL）和通气/氧气摄取量。两种饮食后运动后期，动脉血pH、PCO₂、乳酸和β-羟基丁酸以及特定通气量均达到稳定水平。尽管两种饮食之间动脉血乳酸和β-羟基丁酸存在差异，但动脉血pH和特定通气量相同。碳水化合物饮食后R和RQL均高于脂肪饮食后，且R和RQL之间无系统性差异。因此，在极端饮食后的次最大运动期间，R似乎可以估计骨骼肌中脂肪和碳水化合物氧化的比例。
