Pressor response to isometric exercise in patients with multiple sclerosis

Area of Science:

• Cardiovascular Physiology
• Neuroscience
• Autonomic Nervous System Function

Background:

• Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system.
• Autonomic dysfunction is a known complication of MS, impacting various bodily functions.
• Cardiovascular responses to exercise can be altered in neurological conditions.

Purpose of the Study:

• To investigate if patients with multiple sclerosis (MS) display attenuated heart rate and pressor responses during isometric handgrip exercise.
• To assess the relationship between MS and autonomic cardiovascular control during physical exertion.

Main Methods:

• Isometric handgrip exercise at 30% of maximal voluntary contraction (MVC) to fatigue was performed by MS patients and healthy controls.
• Systolic, diastolic, and mean arterial pressure (MAP) were monitored throughout the exercise.
• Heart rate changes were also recorded and analyzed.

Main Results:

• Patients with MS showed significantly lower increases in MAP compared to controls during isometric handgrip exercise.
• The mean change in MAP at fatigue was +28.2 mm Hg in MS patients versus +47.9 mm Hg in controls.
• Heart rate increased normally in MS patients, suggesting a dissociation between heart rate and blood pressure responses.

Conclusions:

• MS lesions may affect autonomic cardiovascular control centers, leading to attenuated pressor responses to exercise in some patients.
• A significant subset of MS patients (17%) demonstrated profound attenuation of pressor response.
• Abnormal dissociation between heart rate and pressor response to static exercise is suggested in MS.