Orthostatic responses in adolescent chronic fatigue syndrome: contributions from expectancies as well as gravity

Abstract

BackgroundOrthostatic intolerance is common in chronic fatigue syndrome (CFS), and several studies have documented an abnormal sympathetic predominance in the autonomic cardiovascular response to gravitational stimuli. The aim of this study was to explore whether the expectancies towards standing are contributors to autonomic responses in addition to the gravitational stimulus itself.MethodsA total of 30 CFS patients (12–18 years of age) and 39 healthy controls underwent 20° head-up tilt test and a motor imagery protocol of standing upright. Beat-to-beat cardiovascular variables were recorded.ResultsAt supine rest, CFS patients had significantly higher heart rate, diastolic blood pressure, and mean arterial blood pressure, and lower stroke index and heart rate variability (HRV) indices. The response to 20° head-up tilt was identical in the two groups. The response to imaginary upright position was characterized by a stronger increase of HRV indices of sympathetic predominance (power in the low-frequency range as well as the ratio low-frequency: high-frequency power) among CFS patients.ConclusionsThese results suggest that in CFS patients expectancies towards orthostatic challenge might be additional determinants of autonomic cardiovascular modulation along with the gravitational stimulus per se.

Stress vulnerability in adolescents with chronic fatigue syndrome: experimental study investigating heart rate variability and skin conductance responses

“…In contrast, Wyller et al. () did not find an abnormal response to the standard version of this task, whereas when asked to imagine standing upright, adolescents with CFS showed a significantly stronger increase in sympathetic predominance compared to healthy controls. This indicates that abnormal responses to the head‐up tilt task in adolescents with CFS are not purely the result of the gravitational challenge.…”

An anthropogenic model of cardiovascular system adaptation to the Earth’s gravity as the conceptual basis of pathological anthropology

“…The abovementioned factors result in an increase in the body’s tension in the anti-gravity mode [ 1 – 4 , 6 , 29 , 32 , 35 , 39 , 49 , 51 , 58 ], which actually leads to the development of fatigue syndrome. Several studies have demonstrated an association between chronic fatigue syndrome and orthostatic intolerance, predominantly postural orthostatic tachycardia syndrome [ 7 , 59 , 60 ].…”

Anticipation of and response to exercise in adolescents with CFS: An experimental study

“…This may make exercise harder physically, perpetuating avoidance of it. Through experience, physical activity may become associated with increased fatigue by classical conditioning (10)(11)(12). Furthermore, in theory, expectations may influence the experience of fatigue, creating a vicious cycle whereby the expectation of fatigue being induced by exercise makes it more likely that an individual attends to signs of fatigue in response to exercise.…”