This study is a single-center RCT. Potential subjects with symptomatic non-permanent AF will be enrolled to determine the effect of sprint interval training (SIT) in comparison to moderate-intensity continuous training (MICT) and non-exercise control in reducing AF burden. The Investigators will enroll 60 patients during the first 12 months of the study. Baseline data collection will be conducted during the first month after enrollment. After baseline data collection, subjects will be randomized (1:1:1) to SIT vs. MICT vs. non-exercise controls. The exercise training will last for 3 months followed by final data collection which will be completed in 1 month.