Jørgensen Arve, Ekdahl Anna, Havnes Marianne B, Eftedal Ingrid
Department of Diagnostic Imaging, St. Olavs University Hospital, Post Box 3250, 7006, Trondheim, Norway,
Eur J Appl Physiol. 2015 Mar;115(3):597-605. doi: 10.1007/s00421-014-3046-z. Epub 2014 Nov 14.
Decompression sickness (DCS) caused by vascular bubble formation is a major risk when diving. Prior studies have shown that physical exercise has a significant impact in both reducing and increasing bubble formation. There is limited knowledge about the mechanisms, but there are indications that exercise-induced muscle injury prior to diving may cause increased bubble formation. The purpose of this study was to investigate the role of exercise-induced muscle injury as a possible mechanism of bubble formation during diving.
Muscle injury was induced by exposing female Sprague-Dawley rats (n = 30) to a single bout of eccentric exercise, 100 min intermittent, downhill (-16°) treadmill running. Forty-eight hours later, the animals were exposed to a 50-min simulated saturation dive (709 kPa) in a pressure chamber, when the degree of muscle injury and inflammation would be the most pronounced. Bubble formation after the dive was observed by ultrasonic imaging for 4 h.
No difference in bubble loads was found between the groups at any time despite evident muscle injury. Maximum bubble loads (bubbles cm(-2) heart cycle(-1)) were not different, exercise: 1.6 ± 3.5 SD vs control: 2.2 ± 4.1 SD, P = 0.90, n = 15 in each group.
Eccentric exercise performed 48 h prior to diving causes skeletal muscle injury but does not increase the amount of vascular bubbles in rats. The prevailing recommendation is that physical activity prior to diving is a risk factor of DCS. However, present and previous studies implicate that pre-dive physical activity does not increase the DCS risk.
血管气泡形成导致的减压病(DCS)是潜水时的主要风险。先前的研究表明,体育锻炼对减少和增加气泡形成均有显著影响。关于其机制的了解有限,但有迹象表明,潜水前运动诱发的肌肉损伤可能会导致气泡形成增加。本研究的目的是调查运动诱发的肌肉损伤作为潜水期间气泡形成的一种可能机制所起的作用。
通过让雌性Sprague-Dawley大鼠(n = 30)进行单次离心运动,即100分钟间歇性下坡(-16°)跑步机跑步,诱导肌肉损伤。48小时后,将动物置于压力舱中进行50分钟的模拟饱和潜水(709 kPa),此时肌肉损伤和炎症程度最为明显。潜水后通过超声成像观察4小时的气泡形成情况。
尽管有明显的肌肉损伤,但两组在任何时候的气泡负荷均无差异。最大气泡负荷(气泡数·厘米-2·心动周期-1)无差异,运动组:1.6±3.5标准差,对照组:2.2±4.1标准差,P = 0.90,每组n = 15。
潜水前48小时进行的离心运动可导致骨骼肌损伤,但不会增加大鼠血管气泡的数量。目前普遍的建议是,潜水前的体育活动是减压病的一个危险因素。然而,目前和以往的研究表明,潜水前的体育活动不会增加减压病风险。