We investigated the effects of regular walking in green and suburban environments on heart rate variability (HRV) and blood pressure (BP) in middle-aged adults. Twenty-three adults participated in a non-randomized crossover experiment comprised of once-weekly 50-min moderate-intensity walking sessions. Separated by a two-week washout period, participants walked for three weeks in each of two treatment conditions (green and suburban) in a local arboretum and suburban sidewalks of Chaska, MN. Eleven participants completed green walking first and 12 suburban walking first. Walks were split into 15-min intra-walk phases, with phases representing each walk's beginning, middle, and final 15-min. Repeated measures linear mixed models evaluated (1) HRV phase differences between treatments and HRV change within treatments, and (2) pre- and post-walk BP differences between treatments and pre-to post-walk BP changes. Intra-walk phase analyses revealed higher HRV during green walking vs. suburban walking during phase 2 (p < 0.0001) and phase 3 (p = 0.02). Less HRV reduction was seen between intra-walk phases 1 and 2 during green vs. suburban walking (p = 0.02). Pre-to post-walk changes revealed decreased mean systolic BP for both green (p = 0.0002) and suburban (p = 0.003) walking conditions, but not for diastolic BP. Post-walk BP results were similar after both green walking and suburban walking. In summary, walking sessions in a green environment elicited greater beneficial HRV responses compared to a suburban environment. Additionally, walking in either environment, green or suburban, promoted reductions in systolic BP.

中文翻译：

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绿色步行对心率变异性的影响：一项交叉试验研究。

我们调查了在绿色和郊区环境中常规行走对中年人心率变异性（HRV）和血压（BP）的影响。23名成年人参加了非随机交叉实验，该实验由每周一次的50分钟中等强度步行锻炼组成。分开进行为期两周的冲洗，参与者在明尼苏达州查斯卡的当地植物园和郊区人行道上的两种治疗条件（绿色和郊区）中，每人走了三个星期。11位参与者完成了绿色步行，并且12位郊区完成了步行。将步行分为15分钟的步行内阶段，每个阶段代表开始，中间和最终15分钟的阶段。评估重复测量的线性混合模型（1）治疗之间的HRV相差和治疗内的HRV变化，（2）治疗前后的血压差异以及治疗前后的血压变化。步行内阶段分析显示，绿色步行期间的HRV高于第二阶段（p <0.0001）和第三阶段（p = 0.02）的郊区步行。在绿色步行与郊区步行之间，步行阶段1和2之间的HRV降低较少（p = 0.02）。行走前至行走后的变化表明，在绿色（p = 0.0002）和郊区（p = 0.003）行走条件下，平均收缩压均降低，但对于舒张压却没有。经过绿色步行和郊区步行后，步行后的BP结果相似。总而言之，与郊区环境相比，在绿色环境中散步会引起更大的有益HRV反应。此外，在绿色或郊区环境中行走都有助于减少收缩压。