*3.1. Physical Activity*

All 25 studies assessed the relationship between physical activity and burn-out.

Nine out of ten experimental studies found a positive effect of physical activity on risk of burn-out. More specifically, five studies found a reduction in risk of burn-out in general (i.e., all three dimensions combined) due to physical activity (reduction ranging from 6.9% to 41.3%) [49,52–55]. Two studies assessed the effect of physical activity on all three dimensions of burn-out separately, reporting a positive effect on emotional exhaustion (−33.4% and −10%) and cynicism (−33.3% and −4%), but not on personal accomplishment [51,56]. However, one other study also assessed the effect of physical activity on emotional exhaustion, cynicism and personal accomplishment separately and did not find a significant effect on any dimension [50]. Two of the ten experimental studies assessed the effect of physical activity on emotional exhaustion only and showed a significant improvement in emotional exhaustion (−21.6% and −10%) [47,48].

Four experimental studies also conducted follow-up measurements, with three studies reporting a decrease in risk of burn-out three and six months after the physical activity intervention [47,53,56]. The fourth study equally showed a decrease after six months and this maintained after 12 months [52]. Four studies compared physical activity interventions with other interventions such as multimodal rehabilitation and basic care, but no significant differences in the decrease in burn-out risk between these interventions were reported [49,52,54,56].

All 15 observational studies assessed the relationship between physical activity and risk of burn-out, or one of its components. Fourteen observational studies found a negative association between physical activity and risk of burn-out, or one of its components, and one did not find a relationship. More specifically, ten studies assessed the relationship between physical activity and risk of burn-out generally [21,61,63,64,66–69], of which nine found a negative association and one did not find a significant relation between both [65]. One observational study assessed both the relationship between physical activity and risk of burn-out and all three dimensions separately and found negative associations between physical activity and risk of burn-out, emotional exhaustion and cynicism and a positive association between physical activity and professional efficacy [57]. Four other studies found a negative association between physical activity and emotional exhaustion [46,58,60,70] and one of them also found a positive association between physical activity and cynicism [46]. Lastly, one of 15 observational studies concluded that the association between physical activity and risk of burn-out was stronger in workers with a sedentary job [58].
