Abstract Body: Background: Although the dose-response relationship between aerobic exercise (AE) and blood pressure has been well studied, the dose-response relationship of resistance exercise (RE) combined with AE with blood pressure (BP) is understudied.

Methods: This ongoing randomized controlled trial enrolled 111 participants aged 40 years or older who were inactive, overweight or obese (body mass index [BMI] 25-43kg/m²), and non-smokers. Participants were randomized into one of four groups: 0 minutes (min) (n=30), 15 min (n=28), 30 min (n=26), or 60 min (n=27) of RE twice per week for 6 months. All groups were prescribed 30 min of AE per session following the current US Physical Activity Guidelines recommending both AE and RE. Monthly BP was the average of weekly BP taken before the first exercise of each week. Data was analyzed by a linear mixed model with age, sex, BMI, and month 1 (M1) BP as covariates.

Results: For the 111 participants, mean (standard deviation [SD]) age was 57 (10) years, mean (SD) BMI of 32.5 (4.5) kg/m²; 82 (73.8%) participants were female. Mean (SD) of M1 systolic BP (SBP) was 120.8 (12.8) mmHg and mean (SD) of M1 diastolic BP (DBP) was 80.7 (8.7) mmHg. From M1 to M6, SBP decreased -2.30 (95% CI, -4.29 -0.3: p=0.025) mmHg, while DBP decreased -2.29 (95% CI, -4.32 -0.26: p=0.028) mmHg in overall sample. Neither SBP nor DBP in the RE groups decreased differently than AE alone (control group). Although not statistically different, 15 min of RE, followed by AE alone, appear to be more effective to reduce both SBP and DBP, however more RE (30 min and 60 min) did not show larger reductions in SBP and DBP over 6 months. The SBP mean changes from M1 to M2 are -0.87, -2.04, -0.59, 0.12: M1 to M3 are -1.71, -3.13, -1.76, -0.51: M1 to M4 are -3.77, -4.49, 0.25, -0.98: M1 to M5 are -3.05, -2.64, -1.00, -1.86: and M1 to M6 are -2.73, -3.51, -1.59, -1.37 mmHg for the AE only, 15 min, 30 min, and 60 min groups, respectively. The DBP mean changes from M1 to M2 are -0.92, -1.93, -0.59, 0.14: M1 to M3 are -1.81, -3.01, -1.82, -0.71: M1 to M4 are -3.70, -4.65, 0.11, -1.19: M1 to M5 are -2.88, -2.87, -1.00, -1.94: and M1 to M6 are -2.54, -3.62, -1.72, -1.19 mmHg for the AE only, 15 min, 30 min, and 60 min groups, respectively.

Conclusions: Preliminary data suggest that RE added to AE does not appear to further reduce (or increase) BP in adults with overweight or obesity. A larger sample (n=240) should confirm the findings after the trial is completed.