Low-Level Blast Exposure in Humans A Systematic Review of Acute and Chronic Effects

There is growing concern that military breaching and training and firing artillery and mortars, grenades, and shoulder-fired weapons may have some type of cumulative deleterious effects. There are anecdotal reports of those with repetitive exposure to low-level blast complaining of various symptoms, as well as increasing empirical evidence. The purpose of this report is to provide a systematic review of the literature on repetitive lowlevel blast as it pertains to military and police training protocols. An extensive literature search was conducted, resulting in detailed review of 18 studies. Results suggest few consistent findings, likely due to the heterogeneity of methods, high risk of bias, and lack of reliance on objective blast-exposure data. Adverse effects, when present, dissipated over time. All studies that used blast gauges found significant associations, though only a subset actually reported using the blast-gauge data (to correlate objective exposure with outcomes). When comparing studies within an outcome domain (e.g., cognitive), findings were largely inconsistent. Research with larger sample sizes, followed longitudinally, is needed.