PURPOSE: This study aimed to investigate the effect and carry-over effect of arm swing exercise (ASE) training on cardiac autonomic modulation, cardiovascular risk factors, and blood electrolytes in older persons with prehypertension. METHODS: Subjects were 50 individuals with prehypertension (aged 66.90鈥?/-鈥?.50鈥痽r, body mass index 23.84鈥?/-鈥?.65鈥痥g/m(2)). They were randomly assigned into ASE group and control group. Subjects in the ASE group underwent an ASE training program for 3鈥痬onths鈥痑t a frequency of 30鈥痬in/day, 3 days/week. Subjects in the control group maintained their daily routine activities minus regular exercise. Blood pressure, heart rate variability (HRV), cardiovascular risk factors including blood glucose, lipid profile, high-sensitive C-reactive protein (hsCRP), and electrolytes were evaluated on 3 occasions: before and after the 3-month intervention, and 1 month after intervention ended. RESULTS: Following the 3-month intervention, systolic blood pressure (SBP) and serum hsCRP concentration were significantly lower, while serum high-density lipoprotein (HDL)-cholesterol, potassium (K(+)), magnesium (Mg(2+)) concentrations, standard deviation of normal R-R intervals (RMSSD) and high frequency (HF) power values were higher in the ASE group when compared with the control group (p鈥?鈥?.05). At the 1-month follow-up interval, SBP and serum hsCRP concentration remained lower while serum HDL-cholesterol and K(+) concentrations remained higher in the ASE group as compared to the control group (p鈥?鈥?.05). CONCLUSION: ASE training decreased SBP and serum hsCRP concentration, increased serum HDL-cholesterol, K(+), and Mg(2+) concentrations and increased RMSSD and HF power values in older persons with prehypertension. In addition, there were carry-over effects of ASE training i.e. decreased SBP and serum hsCRP concentration as well as increased serum HDL-cholesterol and K(+) concentrations.