The low tolerance for exercise that is a common complaint after traumatic
brain injury is typically justified by motor impairment or secondary physical
injury. However, a recent study has shown that the low tolerance may also
be related to cardiac fitness.
The study measured the heart rate-at rest and after exercise-of 12 boys
who had survived a severe traumatic brain injury. They found that, as
compared to healthy controls, the TBI survivors had significantly higher
heart rates at rest and after exercise. Although the nature of brain injury
varied between the boys, it was suggested that diffuse axonal injury could
contribute to impairment of the autonomic nervous system.
Additionally, prolonged bed rest and a sedentary lifestyle may contribute
to the difference in heart rates. The authors of the study propose that
it may be a combination of both, and that clinicians and rehabilitation
professional should take the potential for lowered fitness into consideration
when creating a treatment plan.
Katz-Leurer M, Rotem H, Keren O, & Meyer S. Heart rate and heart rate
variability at rest and during exercise in boys who suffered a severe
traumatic brain injury and typically-developed controls. Brain Injury.