**3. Results**

In total, 18,536 articles were found. When removing all duplicates, 4907 articles remained. Titles and abstracts were screened for eligibility. Of the 109 remaining articles, sixteen studies met the inclusion criteria. In addition, a forward and backward search was performed through which we identified six more studies. Another two articles were included after screening the reference lists of two previously published systematic reviews investigating the association between physical activity and burn-out [1,6]. One more article was obtained through hand search [46]. So, in total, 25 articles were included in the final synthesis. The flow chart of the search process is displayed in Figure 1.

**Figure 1.** Flow chart of the systematic search.

The 25 included studies consisted of ten experimental and 15 observational studies. The experimental studies included five randomized controlled trials (RCTs), one randomized clinical trial, one quasi experimental and three pre-experimental studies. An overview of the included experimental studies is presented in Table 1. The observational studies included six longitudinal and nine cross-sectional studies. An overview of the included observational studies is presented in Table 2.


 **1.** Overview of the included experimental studies.

**Table**


**Table 1.** *Cont.*

*Nutrients* **2020**, *12*, 397




Activity (PA) Intervention group (IG), Control group (CG), Randomised

 Controlled Trial (RCT).

**Table 1.** *Cont.*








Abbreviations: Maslach Burn-out Inventory (MBI), Shirom-Melamed Burn-out Questionnaire (SMBQ), The Oldenburg Burn-out Inventory (OBI), Copenhagen Burn-out Inventory (CBI), Physical Activity (PA) Low Physical Activity (LPA), Moderate-to-vigorous Physical activity (MVPA), Intervention Group (IG), Control Group (CG), Randomised Controlled Trial (RCT).
