Physical activity level and cardiovascular strain in wildland firefighters during forest fire suppression: an exploratory study

Abstract Introduction: wildland fire suppression exposes firefighters to high cardiovascular risk. Objective: to evaluate the physical activity level (PAL), sedentary behavior (SB) and cardiovascular strain of wildland firefighters during a large fire suppression. Methods: for 9 days, 24h/day, we evaluated 7 male wildland firefighters. Participants had their heart rate (HR) measured every second and physical activity recorded by an accelerometer sensor every 60 seconds. The mean records of the 2nd, 3rd and 4th days of fire suppression were computed for the analysis. PAL was evaluated by the vector magnitude and cardiovascular strain by HR intensity. Results: the volunteers spent on average 112 (SD 24) min/day in moderate to vigorous physical activity (MVPA), achieved 14,803 (SD 1,667) steps/day and spent 1,860 (SD 481) kcal/day. Cardiovascular strain remained on average at 47 (SD 42) min/day of vigorous effort and 8 (SD 12) min/day of very vigorous physical activity. Conclusion: the firefighters evaluated during a large-scale wildland fire suppression accounted for more than double of the minimum recommended MVPA/week in three days, showed more than 50 min/day of high cardiovascular strain, and little time on sedentary behavior compared to other professions.

摘要与研究背景：野外灭火作业会使消防员面临较高的心血管疾病风险。
研究目的：评估大规模野外灭火作业期间，野外消防员的身体活动水平（Physical Activity Level, PAL）、久坐行为（Sedentary Behavior, SB）及心血管负荷。
研究方法：本研究在9天内每日24小时对7名男性野外消防员开展评估。研究人员以每秒1次的频率采集受试者的心率（Heart Rate, HR）数据，并通过加速度传感器每60秒记录一次身体活动信息。本研究选取灭火作业第2、3、4天的记录数据计算均值，用于后续分析。其中，身体活动水平通过矢量幅值进行评估，心血管负荷则通过心率强度进行量化。
研究结果：受试者日均中等至高强度身体活动（Moderate to Vigorous Physical Activity, MVPA）时长为112分钟（标准差SD=24），日均步数达14803步（SD=1667），日均能量消耗为1860千卡（SD=481）。心血管负荷方面，日均高强度活动时长为47分钟（SD=42），极高强度活动时长为8分钟（SD=12）。
研究结论：本次针对大规模野外灭火作业期间消防员的评估结果显示，受试者3天内的中等至高强度身体活动量达到每周推荐最低值的2倍以上，日均高心血管负荷时长超过50分钟，且与其他职业相比，其久坐行为占比极低。