Kadoya Manabu, Izumi Hiroyuki, Kubota Makoto, Yamashita Tsuyoshi, Kumashiro Masaharu
The Department of Ergonomics, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan.
Sangyo Eiseigaku Zasshi. 2010;52(1):12-20. doi: 10.1539/sangyoeisei.b9011. Epub 2009 Dec 14.
It is necessary to try to achieve quick recovery from work strain by setting adequate breaks and shortening continuous working hours to prevent the accumulation of fatigue. However, there has been no research investigating the influence of the timing and lengths of breaks on individual aerobic capacities in recovery from work strain. In this study, we set three load patterns based on the length and timing of breaks: "no breaks", "one break" and "regular small breaks". We examined the differences of the heart rate variation in the recovery time after working considering the individual aerobic capacities (VO(2)max) of ten male subjects (mean age 22.3 +/- 1.7 yr) in the case of 50 W or 100 W workloads on a bicycle ergometer. When individual aerobic capacity was not considered, the "regular small breaks" condition led to the quickest recovery to the level of the resting heart rate at 50 W workload. Not all conditions showed heart rate recovery within 30 min at 100 W workload. On the other hand, when individual aerobic capacity was considered, the "regular small breaks" condition showed the quickest recovery to the level of the resting heart rate at 50 W workload in the low aerobic capacity group (VO(2)max mean 42.2 +/- 3.7 ml/kg/min). However, in the high aerobic capacity group (VO(2)max mean 54.5 +/- 4.1 ml/kg/min), the "regular small breaks" condition resulted in the quickest recovery of the level to the resting heart rate at 100W workload. Two-way repeated measures ANOVA was performed for the recovery time with respect to the rate of increase from resting heart rate to examine the influence on heart rate recovery of physical activity loads, workload patterns and individual fitness. Physical activity loads were strongly related to the increase from resting heart rate in recovery time, and workload patterns showed that the regular small breaks condition was related to the heart rate recovery in the high fitness subjects in the case of the exercise intensity of 100 W. The effect of work strain decreased by workload patterns was defined by the relationship between physical activity load and individual fitness. In future occupational health activities, it will be important to manage work in order to aim for quick recovery from work strain by using ergonomics. The evaluation of the level of the physical activity load and distribution of proper break times during working in addition to individual aerobic capacities are important in considerations of quick recovery from work strain.
通过设置适当的休息时间和缩短连续工作时长来防止疲劳积累，从而努力实现从工作压力中快速恢复是很有必要的。然而，尚无研究调查休息时间的安排和时长对从工作压力中恢复时个体有氧能力的影响。在本研究中，我们根据休息时间的长度和安排设置了三种负荷模式：“无休息”、“一次休息”和“定期短休息”。我们在自行车测力计上，针对10名男性受试者（平均年龄22.3±1.7岁）在50W或100W工作量情况下的个体有氧能力（最大摄氧量），研究了工作后恢复时间内心率变化的差异。当不考虑个体有氧能力时，在50W工作量下，“定期短休息”状态导致恢复到静息心率水平的速度最快。在100W工作量下，并非所有状态都能在30分钟内使心率恢复。另一方面，当考虑个体有氧能力时，在低有氧能力组（最大摄氧量平均为42.2±3.7毫升/千克/分钟）中，“定期短休息”状态在50W工作量下恢复到静息心率水平的速度最快。然而，在高有氧能力组（最大摄氧量平均为54.5±4.1毫升/千克/分钟）中，“定期短休息”状态在100W工作量下恢复到静息心率水平的速度最快。对从静息心率上升速率的恢复时间进行双向重复测量方差分析，以研究身体活动负荷、工作量模式和个体健康状况对心率恢复的影响。身体活动负荷与恢复时间内从静息心率的上升密切相关，工作量模式表明，在100W运动强度下，定期短休息状态与高健康水平受试者的心率恢复有关。工作量模式导致的工作压力影响的降低是由身体活动负荷与个体健康状况之间的关系所定义的。在未来的职业健康活动中，利用人体工程学来管理工作以实现从工作压力中快速恢复将很重要。除了个体有氧能力外，评估身体活动负荷水平以及工作期间适当休息时间的分配对于考虑从工作压力中快速恢复也很重要。
