- a Autonomic and Neurovascular Medicine Unit, Department of Medicine, Division of Brain Sciences, Faculty of Medicine, Imperial College London at St Mary's Hospital, UK
- b Autonomic Unit, National Hospital for Neurology & Neurosurgery, Queen Square/Division of Clinical Neurology, Institute of Neurology, University College London, London, UK
- c Department of Physiology and Pharmacology & Post-Graduate Program in Cardiovascular Sciences, Fluminense Federal University, Niterói, RJ, Brazil
Abstract
The
autonomic nervous system closely integrates a range of vital processes,
including, cardiovascular function.
Physical activity, or exercise,
requires a range of integrated autonomic and cardiovascular adjustments
in order to maintain homeostasis.
Pathological conditions that result in
dysfunction of the autonomic nervous system, such as autonomic failure,
can therefore jeopardize the control of blood pressure resulting in
hypotension and have serious implications for health.
Exercise induced
hypotension, defined as a ≥ 10 mm Hg fall in systolic blood pressure
during exercise, can be a significant symptom/event for autonomic
failure, as well as other autonomic disorder, patients, including,
Multiple System Atrophy and Spinal Cord Injury, and can reduce physical
capacity, orthostatic tolerance, result in falls, complicate management
and reduce quality of life.
The likely mechanisms do not appear to be an
altered cardiac output or active muscle vasodilation response to
exercise, but rather, a lack of and/or a blunted increase in sympathetic
nerve activity during exercise and/or excessive vasodilation in the
splanchnic circulation.
The severity of exercise induced hypotension
seems to be higher during dynamic relative to static exercise.
The
possible management strategies for exercise induced hypotension include
both non-pharmacological, e.g., reducing risk factors, and
pharmacological measures, such as sympathomimetics, but studies on other
pharmacological agents are limited.
