Deconditioning in patients with orthostatic intolerance

Neurology. 2012 Oct 2;79(14):1435-9. doi: 10.1212/WNL.0b013e31826d5f95. Epub 2012 Sep 19.


Objective: To study the frequency and degree of deconditioning, clinical features, and relationship between deconditioning and autonomic parameters in patients with orthostatic intolerance.

Methods: We retrospectively studied all patients seen for orthostatic intolerance at Mayo Clinic between January 2006 and June 2011, who underwent both standardized autonomic and exercise testing.

Results: A total of 184 patients (84 with postural orthostatic tachycardia syndrome [POTS] and 100 without orthostatic tachycardia) fulfilled the inclusion criteria. Of these, 89% were women, and median age was 27.5 years (interquartile range [IQR] 22-37 years). Symptom duration was 4 years (IQR 2-7.8). Of the patients, 90% had deconditioning (reduced maximum oxygen uptake [VO(2max)%] <85%) during exercise. This finding was unrelated to age, gender, or duration of illness. The prevalence of deconditioning was similar between those with POTS (95%) and those with orthostatic intolerance (91%). VO(2max)% had a weak correlation with a few autonomic and laboratory parameters but adequate predictors of VO(2max)% could not be identified.

Conclusion: Reduced VO(2max)% consistent with deconditioning is present in almost all patients with orthostatic intolerance and may play a central role in pathophysiology. This finding provides a strong rationale for retraining in the treatment of orthostatic intolerance. None of the autonomic indices are reliable predictors of deconditioning.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Pressure
  • Cardiovascular Deconditioning / physiology*
  • Exercise Test
  • Female
  • Heart Rate
  • Humans
  • Male
  • Orthostatic Intolerance / complications*
  • Postural Orthostatic Tachycardia Syndrome / complications*
  • Reflex
  • Retrospective Studies
  • Statistics, Nonparametric
  • Valsalva Maneuver / physiology
  • Young Adult