Paolo T. Pianosi, Eric Emerling, Kristin C. Mara, Amy L. Weaver, Philip R. Fischer
Pediatric & Adolescent Medicine, Mayo Clinic, 55905 Rochester, USA. E-mail: pianosi.paolo@mayo.edu
DOI: 10.2340/16501977-2221

Objective: Chronic fatigue and chronic pain both deter people from participating in exercise, even though exercise is often a key component of treatment. While reasons for this may seem obvious, the extent and mechanism(s) of reduced exercise performance among affected individuals, particularly those with chronic pain, are not well described. We hypothesized that patients with chronic fatigue are more deconditioned than those with chronic pain, due to the nature of their illness or disability.
Design: Retrospective chart audit June 2012 to December 2014.
Subjects: Adolescents with chronic fatigue (320, 73 males) or chronic pain (158, 30 males).
Methods: Maximal cardiopulmonary exercise test to determine peak oxygen uptake (V̇O2) and work efficiency.
Results: Mean (standard deviation (SD)) peakV̇O2 was similar between patients with chronic fatigue and chronic pain: males 36. 5 (SD 8. 3) vs 34. 2 (SD 7. 3) ml/kg/min (p = 0. 17); females 27. 3 (SD 6. 1) vs 27. 6 (SD 6. 6) ml/kg/min (p = 0. 67). PeakV̇O2 was < 90% predicted in 80% and 75% of females, or 77% and 83% of males, with chronic fatigue and
chronic pain, respectively. Peak O2pulse and work efficiency were likewise similar.
Conclusion: Patients in both groups manifest exercise responses typical of cardiopulmonary deconditioning and to similar extent. Failure to detect unique cardiopulmonary or muscle pathophysiology suggests a shared pathway to low aerobic work capacity.

Little is known about fitness in patients with chronic pain, but chronic pain, like chronic fatigue, deters exercise. This becomes problematic since exercise is a key component of treatment and rehabilitation. We wondered whether adolescents with chronic fatigue are more deconditioned than those with chronic pain due to the nature of their illness or disability. We conducted exercise tests in nearly 500 adolescents with chronic pain or chronic fatigue to determine physical fitness. We found aerobic fitness was low, but similar, in 75%-80% of patients with chronic fatigue or chronic pain; and all exhibited typical features of deconditioning or being “out of shape”. Moreover, their muscles appeared to work normally, apart from the obvious reduction in peak exercise capacity. We conclude patients with either chronic pain or chronic fatigue suffer similar consequences of inactivity, regardless of the reason for curtailing exercise.