Purpose: To examine the influence of a unilateral exercise training protocol on brachial artery reactivity (BAR) in 12 men (aged 81 ± 5 yr).
Methods: Brachial artery diameters and blood flow parameters were assessed, in both arms, using high-resolution ultrasonography, before and after 5 min of forearm occlusion, before and at the end of each week of a 4-wk training program. Training consisted of a unilateral handgrip training protocol (nondominant arm) at 60% of maximal voluntary handgrip strength, performed for 4 wk, 4 d·wk−1, 20 min per session, and a cadence of one contraction per 4 s.
Results: After training, handgrip strength increased 6.2% (baseline = 32.4 ± 7.0 kg vs week 4 = 34.4 ± 6.7 kg) in the trained arm only but failed to reach statistical significance (P = 0.10). No statistical changes were observed for blood pressure or resting HR. In contrast, BAR increased 45% (Pre = 2.9% vs Post = 4.1%, P = 0.05) in the trained arm only. Improvements in BAR were observed after the second week of training, without significant changes in the main vasodilatory trigger, defined as the relevant shear stimulus after forearm occlusion (P > 0.05).
Conclusions: These data indicate that a localized short-term exercise program results in significant improvements in vascular function in the trained arm of elderly men compared with the control arm. Furthermore, the findings indicate a statistically significant increase in BAR at the end of the second week of training, despite a similar trigger for dilation versus before training.
1Wake Forest University, Winston-Salem, NC; 2Pennington Biomedical Research Center, Baton Rouge, LA; 3Louisiana State University Health Sciences Center, Baton Rouge, LA; 4Louisiana State University, Baton Rouge, LA; and 5Tulane University Health Sciences Center, New Orleans, LA
Address for correspondence: Michael A. Welsch, Ph.D., Department of Kinesiology Louisiana State University, 112 Long Field House Baton Rouge, LA 70803; E-mail: email@example.com.
Submitted for publication September 2008.
Accepted for publication December 2008.