Pressor response to isometric exercise in patients with multiple sclerosis

PEPIN, ERIC B.; HICKS, RICHARD W.; SPENCER, MARK K.; TRAN, ZUNG V.; JACKSON, CATHERINE G. R.

Medicine & Science in Sports & Exercise: June 1996 - Volume 28 - Issue 6 - pp 656-660
Clinical Sciences: Clinical Investigations

The purpose of this study was to determine whether patients with multiple sclerosis (MS) would show attenuated heart rate and/or pressor responses to isometric handgrip exercise. Patients with MS (30 males, 74 females, aged 23-61 yr) and control subjects (9 males, 16 females, aged 25-47 yr) performed isometric handgrip exercise at 30% of maximal voluntary contraction (MVC) to fatigue. Systolic, diastolic, and mean arterial pressure (MAP) increased linearly in both groups, but were significantly lower (P<0.05) in patients with MS at 20%, 40%, 60%, 80%, and 100% of exercise duration. Mean change in MAP at fatigue was +47.9 mm Hg for controls and +28.2 mm Hg for patients with MS, with 18 patients with MS between -6 mm Hg and +15 mm Hg. Heart rate increased normally in patients with MS. To predict change in MAP at fatigue in patients with MS, stepwise regression analysis using six variables yielded an R2 of 0.26. These data suggest that in some patients MS lesions exist in areas of autonomic cardiovascular control that result in attenuated pressor responses to exercise. In 17% of patients tested, attenuation was profound. Data also suggest an abnormal dissociation between the heart rate and pressor response to static work in patients with MS.

Northeastern University, Boston, MA 02115

Submitted for publication September 1994.

Accepted for publication January 1996.

Address for correspondence: Eric B. Pepin, Ed.D., 100 Dockser Hall, Northeastern University, Boston, MA 02115.

©1996The American College of Sports Medicine