Integrative Laboratory of Applied Physiology and Lifestyle Medicine, The University of Iowa, Iowa City, Iowa, United States.
Abboud Cardiovascular Research Center, The University of Iowa, Iowa City, Iowa, United States.
J Appl Physiol (1985). 2023 Oct 1;135(4):812-822. doi: 10.1152/japplphysiol.00052.2023. Epub 2023 Aug 10.
To examine the effects of daily step count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Ten healthy participants (5 females, 30 ± 7 yr) completed four different daily step counts-2,000 (2 K), 5,000 (5 K), 10,000 (10 K), and 15,000 (15 K) steps-on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FAT) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-min following consumption of an HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), nonesterified fatty acids (NEFAs), insulin, and glucose. Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2 K versus 10 K (+23 ± 8 mg/dL, = 0.027), and NEFAs were significantly higher after 15 K versus 2 K (+86 ± 23 µmol/L; = 0.006). No differences were found for insulin, glucose, or REE among conditions (all > 0.124). Similarly, RER ( = 0.054; η = 0.24) and FAT ( = 0.071; η = 0.23) were not significantly different among conditions. In young adults, 10 K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15 K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity. This randomized controlled trial demonstrated that walking 10,000, compared with 2,000, steps/day significantly reduced postprandial lipemia (PPL), an independent predictor of cardiovascular disease (CVD) following same-day evening meal consumption. These experimental data support walking 10,000 steps/day to lower CVD risk.
为了研究每日步数对当天脂肪氧化和餐后高糖混合餐（HFMM）代谢反应的影响。10 名健康参与者（女性 5 名，30±7 岁）分别在 4 天内随机完成 4 种不同的每日步数任务：2000 步（2K）、5000 步（5K）、10000 步（10K）和 15000 步（15K）。在实验日，参与者在室内轨道上以 100 步/分钟的速度分 3 次大致相等的时间段全天吃完相同的食物并完成所有的步行任务。在最后一次步行后，测量参与者的静息能量消耗（REE）、呼吸交换率（RER）和脂肪氧化率（FAT）。在进食 HFMM（960 千卡；48%脂肪）前（BL）和 30、60、90、120 和 240 分钟后采集血样，以测量甘油三酯（即餐后脂血症；PPL）、非酯化脂肪酸（NEFA）、胰岛素和血糖。双因素方差分析表明条件效应，与 10K 相比，2K 后 PPL 显著升高（+23±8mg/dL，=0.027），与 2K 相比，15K 后 NEFA 显著升高（+86±23µmol/L；=0.006）。条件之间的胰岛素、葡萄糖或 REE 没有差异（均 > 0.124）。同样，RER（=0.054；η=0.24）和 FAT（=0.071；η=0.23）在条件之间也没有显著差异。在年轻人中，10K 步引起的 PPL 下降最大，PPL 是心血管疾病的一个独立危险因素。15K 条件后 NEFA 水平最高，可能是由于脂肪组织脂肪分解或脂蛋白脂肪酶活性改变导致活动增加。这项随机对照试验表明，与每天走 2000 步相比，每天走 10000 步显著降低了餐后脂血症（PPL），这是当天晚上用餐后心血管疾病（CVD）的一个独立预测因素。这些实验数据支持每天走 10000 步来降低 CVD 风险。
