1Human Environmental Physiological Research Unit, University of Ottawa, Ontario, CANADA; 2Faculty of Physical Education and Sports, University of Sherbrooke, Sherbrooke, Quebec, CANADA; 3Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Alberta, CANADA; and 4FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, GREECE.
Med Sci Sports Exerc. 2015 Jun;47(6):1281-90. doi: 10.1249/MSS.0000000000000537.
The aging-induced reduction in whole-body heat loss (HL) capacity generates concerns regarding the continued participation of older workers in occupations such as firefighting. We compared HL and change in body heat storage (S) during intermittent exercise in warm/dry and warm/humid conditions among older male firefighters (OLDER, n = 9, age = 54.7 ± 2.1 yr), older (age-matched) nonfirefighters (NON-FF, n = 9, age = 52.8 ± 1.2 yr), and young firefighters (YOUNG, n = 6, age = 26.7 ± 0.8 yr).
We measured evaporative heat loss and dry heat exchange via the Snellen whole-body direct calorimeter while participants performed four 15-min bouts of cycling at 400 W of metabolic heat production separated by 15-min recovery periods in warm/dry (35 °C, 20% relative humidity) and warm/humid (35 °C, 60% relative humidity) conditions.
We found no differences (P > 0.05) in HL or cumulative S (ΔS) between OLDER and NON-FF in the warm/dry (ΔS: OLDER = 233 ± 26 kJ, NON-FF = 270 ± 29 kJ) or warm/humid (ΔS: OLDER = 548 ± 24 kJ, NON-FF = 504 ± 47 kJ) conditions. The OLDER and NON-FF had lower HL than the YOUNG during exercise in both environmental conditions (P < 0.05). The OLDER stored 40% (P > 0.05) and 46% (P = 0.004) more heat than YOUNG in the warm/dry and warm/humid conditions, respectively. The NON-FF stored 63% (P = 0.016) and 34% (P = 0.025) more heat than the YOUNG in the dry and humid conditions, respectively.
Older firefighters and age-matched nonfirefighters demonstrate similar HL and S during work in the heat. Moreover, HL is significantly reduced in older compared to younger firefighters during exercise in both warm/dry and warm/humid conditions. Consequently, older firefighters may be more susceptible to thermal injury while on duty than their younger counterparts.
随着年龄的增长，全身热量损失（HL）能力下降，这引发了人们对老年工人继续从事消防等职业的担忧。我们比较了老年男性消防员（OLDER，n=9，年龄=54.7±2.1 岁）、年龄匹配的非消防员（NON-FF，n=9，年龄=52.8±1.2 岁）和年轻消防员（YOUNG，n=6，年龄=26.7±0.8 岁）在温暖/干燥和温暖/潮湿环境中间歇性运动期间的 HL 和体热储存（S）的变化。
我们使用 Snellen 全身直接量热仪测量蒸发散热和干热交换，参与者在代谢热产生 400 W 下进行四次 15 分钟的骑行，每次骑行之间有 15 分钟的恢复期，在温暖/干燥（35°C，20%相对湿度）和温暖/潮湿（35°C，60%相对湿度）条件下进行。
我们发现 OLDER 和 NON-FF 在温暖/干燥（ΔS：OLDER=233±26 kJ，NON-FF=270±29 kJ）或温暖/潮湿（ΔS：OLDER=548±24 kJ，NON-FF=504±47 kJ）条件下的 HL 或累积 S（ΔS）没有差异（P>0.05）。在两种环境条件下，OLDER 和 NON-FF 的 HL 均低于 YOUNG（P<0.05）。在温暖/干燥和温暖/潮湿条件下，OLDER 分别比 YOUNG 多储存 40%（P>0.05）和 46%（P=0.004）的热量。NON-FF 在干燥和潮湿条件下分别比 YOUNG 多储存 63%（P=0.016）和 34%（P=0.025）的热量。
老年消防员和年龄匹配的非消防员在高温环境下工作时，HL 和 S 相似。此外，与年轻消防员相比，在温暖/干燥和温暖/潮湿条件下运动时，OLDER 的 HL 明显降低。因此，与年轻消防员相比，老年消防员在值班时可能更容易受到热伤害。
