Horswill C A, Zipf W B, Kien C L
Department of Pediatrics, Ohio State University, Columbus, USA.
Med Sci Sports Exerc. 1997 Sep;29(9):1263-8. doi: 10.1097/00005768-199709000-00021.
To determine whether a 13C-bicarbonate, isotope dilution technique could be used to estimate relative changes in energy expenditure of leisure activities of short duration, we studied eight adolescents who performed the following activities: watching television (120 min); playing a stringed instrument (60 min plus 60 min of sitting); and walking plus rest during two approximately isocaloric sessions (slow walk at 40% of peak VO2 for 43 min plus 77 min of sitting; fast walk at 73% of peak VO2 for 22 min plus 98 min of sitting). The rate of appearance of CO2 (RaCO2) was determined from the ratio of the oral dose of 13C-bicarbonate and the isotopic enrichment of breath CO2. The net rates of excretion of CO2 (VCO2) and oxygen consumption were measured. VCO2 and RaCO2, were correlated (r = 0.93; P < 0.05). To adjust for the systematic difference in CO2 production between methods, determinations were expressed as a fraction of that during television viewing. For RaCO2, the ratios for instrument playing, walking at 40% peak VCO2, and walking at 73% peak VO2 were respectively 133 +/- 20%, 186 +/- 38%, and 206 +/- 34%; for VCO2, the respective ratios were 129 +/- 19, 210 +/- 50, and 232 +/- 39 (P > 0.05 for methods and interaction, two-way ANOVA). RaCO2 may be a useful method for detecting relative differences in energy expenditure associated with leisure activities of brief duration.
为了确定13C-碳酸氢盐同位素稀释技术是否可用于估算短时间休闲活动能量消耗的相对变化,我们研究了8名青少年,他们进行了以下活动:看电视(120分钟);弹奏弦乐器(60分钟加60分钟坐着休息);以及在两个热量大致相等的时段内进行步行加休息(以峰值VO2的40%慢走43分钟加77分钟坐着休息;以峰值VO2的73%快走22分钟加98分钟坐着休息)。二氧化碳的出现率(RaCO2)通过口服13C-碳酸氢盐剂量与呼出二氧化碳的同位素富集率之比来确定。测量了二氧化碳的净排出率(VCO2)和耗氧量。VCO2与RaCO2相关(r = 0.93;P < 0.05)。为了校正不同方法之间二氧化碳产生的系统差异,测定结果表示为看电视时测定值的分数。对于RaCO2,弹奏乐器、以40%峰值VCO2步行和以73%峰值VO2步行时的比值分别为133±20%、186±38%和206±34%;对于VCO2,相应比值分别为129±19、210±50和232±39(方法和交互作用的P>0.05,双向方差分析)。RaCO2可能是检测与短时间休闲活动相关的能量消耗相对差异的一种有用方法。