Gutin Bernard, Yin Zenong, Humphries Matthew C, Barbeau Paule
Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Augusta, GA, USA.
Am J Clin Nutr. 2005 Apr;81(4):746-50. doi: 10.1093/ajcn/81.4.746.
It is unclear how moderate and vigorous intensities of physical activity (PA) are associated with cardiovascular fitness (CVF) and percentage of body fat (%BF) in adolescents.
We tested the hypothesis that vigorous PA, to a greater degree than moderate PA, would be associated with better CVF and lower %BF.
This was a cross-sectional study of 421 black and white high school students (x age: 16 y). PA was measured with 5 d of accelerometry and expressed in min/d of moderate or vigorous PA. CVF was measured with a multistage treadmill test and was expressed as the oxygen consumption at a heart rate of 170 bpm. %BF was measured with dual-energy X-ray absorptiometry. Multiple regressions were used to determine the degree to which variance in CVF and %BF was explained by PA, after control for age, sex, race, and the sex x race interaction.
A higher index for CVF was associated with higher amounts of moderate and vigorous PA; more variance was explained by vigorous than by moderate PA. Lower %BF was associated with higher amounts of vigorous PA but not with the amount of moderate PA.
Black and white adolescents who engaged in relatively large amounts of free-living vigorous exercise were likely to be relatively fit and lean.
目前尚不清楚中等强度和高强度身体活动（PA）与青少年心血管健康（CVF）及体脂百分比（%BF）之间的关联。
我们检验了这样一个假设，即与中等强度PA相比，高强度PA与更好的CVF和更低的%BF相关。
这是一项针对421名黑人和白人高中生（平均年龄：16岁）的横断面研究。通过5天的加速度计测量PA，并以中等强度或高强度PA的分钟/天来表示。通过多级跑步机测试测量CVF，并表示为心率170次/分钟时的耗氧量。通过双能X线吸收法测量%BF。在控制年龄、性别、种族以及性别×种族交互作用后，使用多元回归来确定PA对CVF和%BF方差的解释程度。
较高的CVF指数与较高的中等强度和高强度PA量相关；高强度PA比中等强度PA解释了更多的方差。较低的%BF与较高的高强度PA量相关，但与中等强度PA量无关。
进行相对大量自由生活高强度运动的黑人和白人青少年可能相对健康且苗条。
