Cerebral Blood Flow and Heart Rate Variability in Chronic Fatigue Syndrome: A Randomized Cross-Over Study (2018)

hixxy · Jan 23, 2018

Cerebral Blood Flow and Heart Rate Variability in Chronic Fatigue Syndrome: A Randomized Cross-Over Study.
Malfliet A, Pas R, Brouns R, De Win J, Hatem SM, Meeus M, Ickmans K, van Hooff RJ, Nijs J.

Abstract

BACKGROUND:
Pain, fatigue, and concentration difficulties are typical features of chronic fatigue syndrome (CFS). The exact underlying mechanisms of these symptoms are still unknown, but available evidence suggests an important role for impaired pain modulation. As evidence also suggests that pain modulation is related to cardiovascular mechanisms, it seems logical to investigate whether cerebral blood flow (CBF) and heart rate variability (HRV) are altered in these patients.

OBJECTIVES:
We aimed to investigate the role of the cardiovascular system in pain modulation and symptoms of CFS; the response of CBF and HRV to physical stress and their relation to the change in temporal summation (TS) of pressure pain and self-reported symptoms was evaluated.

STUDY DESIGN:
A controlled, randomized cross-over trial.

SETTING:
University Hospital Brussels.

METHODS:
Twenty CFS patients and 20 sedentary healthy controls were included in this study. In both of the groups, the change in TS of pressure pain, CBF (using transcranial Doppler), and HRV (using finger plethysmography) was examined during physical and emotional stress (to control for potential bias), as well as their association mutually and with self-reported symptoms of pain, fatigue, and concentrations difficulties.

RESULTS:
There was no significant interaction or group (F-values ranging from .100 to 1.862, P-values ranging from .754 to .181) effect in CBF or HRV parameters. HRV and CBF did change during physical exercise, but the changes did not differ between patients and controls. While pain scores during TS at the trapezius site reduced in the control group after the physical exercise protocol (P = .037), they did not change in the CFS group (P = .108), suggesting impaired pain modulation. There were no significant correlations between CBF, HRV, TS, and self-reported symptoms (all P-values of correlation analyses > .01).

LIMITATIONS:
Although effect sizes were medium to large, the study sample was relatively low. Also, the mild nature of the exercise bout is discussable. Nonetheless, this mild exercise was able to provoke endogenous pain modulation in the control group, which endorsed a proper execution of the cycling exercise. Moreover, mild exercises are more applicable to daily physical activities in CFS patients than vigorous exercises.

CONCLUSION:
These results seem to refute the previously suggested alterations of CBF/HRV in CFS patients. These cardiovascular parameters appear not to explain pain before, during, and following exercise.
Click to expand...

https://www.ncbi.nlm.nih.gov/pubmed/29357332

MeSci · Jan 23, 2018

hixxy said: ↑

https://www.ncbi.nlm.nih.gov/pubmed/29357332
Click to expand...

I think that Nijs and some others may be rather dodgy, going by some of the reports on PR: http://forums.phoenixrising.me/index.php?search/44695946/&q=nijs&o=date

James · Jan 23, 2018

CPET has shown the differences between groups is not apparent until the repeat session. HRV by finger sensor lacks the accuracy of chest straps when comparisons have been carried out using elite athletes, something that neither group meet criteria for and that brings up criteria used for selection of the CFS group. Had hoped for something better when Jo Nijs name was listed.

Snow Leopard · Jan 25, 2018

The results of this study are likely true -there is no major effect of HRV or cerebral blood flow post 'mild' exercise.

I am basing my opinion on other heart rate and blood flow studies that have been equivocal overall.

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Cerebral Blood Flow and Heart Rate Variability in Chronic Fatigue Syndrome: A Randomized Cross-Over Study (2018)

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