Comparison of Low-Intensity and High-Intensity Exercise in Salivary Nitric Oxide Response: A Pilot Study

Background: Excessive production of salivary nitric oxide (s-NO) is a risk factor for oral diseases such as Sjögren syndrome and periodontal disease. Although s-NO is known to be affected by exercise, it is unclear how the difference in exercise intensities affects the s-NO response. Objectives: The purpose of this study was to investigate the acute effect of different exercise intensities (high vs. low intensity) on s-NO production using a cross-over design. Methods: Five healthy male young adults (21.6 ± 0.9 years) performed two ergometer exercises for 30 min at different exercise intensities: 50% heart rate (HR)reserve (low-intensity condition) and 80% HRreserve (high-intensity condition). Saliva samples were collected before (pre) and after (post 0-h and post 1-h) exercises. Results: The s-NO concentration significantly increased (P < 0.05) after the high-intensity exercise (∆changes in post 0-h; +244 ± 53 µmol/L, post 1-h; +352 ± 58 µmol/L), but the s-NO concentration did not change after the low-intensity exercise (∆changes in post 0-h; +11 ± 37 µmol/L, post 1-h; +64 ± 69 µmol/L). Conclusions: This study reveals that s-NO production is dependent on exercise intensities, suggesting that low-intensity exercise can be possible without increasing the risk of oral diseases.