Parker, Romy, Higgins, Zeenath, Mlombile, Zandiswa N P et al. · The South African journal of physiotherapy · 2018 · DOI
This study looked at how warm water bathing affects heart function in people with ME/CFS compared to healthy people. Researchers found that people with ME/CFS had less stable heart rate patterns before entering warm water, but this improved during the water immersion. The heart rate stayed slightly elevated in the ME/CFS group even after leaving the water. Overall, warm water immersion appeared safe and may help with managing ME/CFS symptoms.
Understanding how ME/CFS patients respond to thermal stress is critical for evaluating hydrotherapy as a potential treatment, since autonomic dysregulation is a hallmark feature of the condition. This study provides preliminary safety data and suggests warm water immersion may temporarily improve heart rate variability in ME/CFS patients, which could inform therapeutic protocols. The findings help distinguish ME/CFS cardiovascular responses from healthy controls.
This study does not prove that warm water immersion is an effective long-term treatment for ME/CFS—it only establishes acute responses during a single session. The small sample size (nine per group) limits generalizability, and the study does not assess whether these temporary improvements translate to functional benefits or whether repeated immersion is safe for all ME/CFS patients. The findings are correlational and do not establish mechanistic explanations for the observed differences.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Parker, Romy, Higgins, Zeenath, Mlombile, Zandiswa N P, Mohr, Michaela J, & Wagner, Tarryn L (2018). The effects of warm water immersion on blood pressure, heart rate and heart rate variability in people with chronic fatigue syndrome.. The South African journal of physiotherapy. https://doi.org/10.4102/sajp.v74i1.442
BibTeX
@article{mecfsatlas-parker-2018-effects-warm,
author = {Parker, Romy and Higgins, Zeenath and Mlombile, Zandiswa N P and Mohr, Michaela J and Wagner, Tarryn L},
title = {The effects of warm water immersion on blood pressure, heart rate and heart rate variability in people with chronic fatigue syndrome.},
journal = {The South African journal of physiotherapy},
year = {2018},
doi = {10.4102/sajp.v74i1.442},
note = {PubMed: 30214947},
url = {https://www.mecfsatlas.com/evidence/parker-2018-effects-warm},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/parker-2018-effects-warm
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