A study published in the Oct 2010 issue of the Journal of Strength & Conditioning Research by Collier et al  reports that resistance training (3 sets, 10 reps; upper and lower body at 65% 1 repetition maximum) produces greater increases in limb blood flow and a greater reduction of blood pressure at (40 minutes postexercise) when compared to aerobic exercise.
According to Kathleen Blanchard writing for EmaxHealth.com, the study found a 20 percent reduction in blood pressure at 45 minutes after a resistance training session. This reduction persisted for 24 hours and is equal to or greater than what can occur after use of blood pressure medication, but without side effects.
1. Collier, SR, Diggle, MD, Heffernan, KS, Kelly, EE, Tobin, MM, and Fernhall, B. Changes in Arterial Distensibility and Flow-Mediated Dilation After Acute Resistance vs. Aerobic Exercise. Journal of Strength & Conditioning Research: October 2010 - Volume 24 - Issue 10 - pp 2846-2852