ABSTRACT Introduction: It is possible that physical activity protects the periodontium by mitigating excessive inflammatory response of the individual. There is some evidence from longitudinal studies and a prospective study demonstrating that physically active adults have experienced a decrease in the risk of periodontitis. To date no study has jointly explored the relationship of physical activity and periodontitis using inflammatory biomarkers. Objective: In this regard, the objective was to assess the bone tissue behavior of rats with experimental periodontitis subjected to aquatic exercise. Methods: Twenty-four male Wistar rats were divided into four groups: 1) without periodontitis and without exercise (CS); 2) without periodontitis and with exercise (CE); 3) with periodontitis and without exercise (DPS); 4) with periodontitis and with exercise (DPE). The animals from groups CE and DPE had swimming sessions for four weeks and the DPS and DPE groups were subjected to ligature-induced periodontitis. After 30 days the animals were sacrificed, and had their right and left hemimandibles removed for radiographic and histological analysis. The data obtained were analyzed and evaluated through ANOVA and Tukey tests. Results: Bone loss in the animals from the DPE group was found to be significantly lower (61.7 ± 2.2; p <0.05) than in those from the DPS group (84.5 ± 1.2; p <0.05), while in terms of the number of osteoblasts (DPS=11.0 ± 1.4; DPE=10.7 ± 5.2) and osteocytes (DPS=17.3 ± 3.1; DPE=19.0 ± 4.4), there was no significant decrease (p <0.05) in the groups subjected to experimental periodontitis, regardless of physical exercise. Conclusion: Physical exercise was found to have a protective effect in relation to bone height and did not influence bone density. Level of evidence II; Therapeutic studies - investigation of treatment results.