Figure 3. Changes in the mean heart rate (HR), standard deviation of normal-to-normal interval (SDNN), square root of the mean squared differences of successive normal-to-normal intervals (RMSSD), natural logarithm total power (Ln TP), Ln low-frequency component (LF), Ln high-frequency component (HF), and Ln LF/HF before (pre), immediately (post), 60 min, and 120 min after rest or yoga. Data are expressed as mean ± SD values. * p < 0.05, ** p < 0.01 vs pre, † p < 0.05, †† p < 0.01; CON vs YOG. CON, control trial; YOG, yoga trial.