An interventional study of Cryotherapy in ME/CFS, Fibromyalgia (FM) and Long-COVID, sponsored by Oxford Brookes University. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by Oxford Brookes University · Not applicable, Interventional, and Other
Chronic fatiguing illnesses such as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), Fibromyalgia, and Long COVID are becoming a major global health challenge. They cause severe personal and social strain and have no proven, widely effective treatments. Although these conditions have different names, they share many symptoms: long-lasting fatigue that doesn't improve with rest, worsening of symptoms after activity (post-exertional malaise), difficulties with thinking ("brain fog"), poor sleep, and widespread pain. Increasing evidence shows that these illnesses also share similar underlying biological problems. These include ongoing inflammation, problems with the autonomic nervous system (which controls automatic body functions), poor function of the blood vessels, and reduced energy production in cells.
Whole-Body Cryotherapy (WBCT) is emerging as a promising non-drug treatment that may help break these cycles. WBCT involves very short, controlled exposure to extreme cold (around -110°C to -160°C). This triggers a rapid response across the nervous, immune, and metabolic systems. The cold acts as a powerful stimulus, encouraging the body to reset imbalanced systems. A session briefly narrows blood vessels and then causes them to widen again, improving blood flow and supporting healthy vessel function. WBCT also appears to reduce inflammation, lower oxidative stress, and improve parasympathetic ("rest-and-recover") nervous system activity.
Early studies in ME/CFS and related conditions are encouraging. Small trials have reported reduced fatigue, clearer thinking, and better autonomic regulation after a course of WBCT sessions, with good safety. Research has also shown changes in blood-brain barrier proteins after WBCT, suggesting it may help repair "leaky" barriers that can drive symptoms in ME/CFS and Long COVID.
By acting on inflammation, blood flow, and nervous system balance at the same time, WBCT could offers a scientifically grounded and potentially transformative approach in understanding the mechanism behind observed treatment effect.
Chronic fatiguing illnesses such as ME/CFS, Fibromyalgia, and Long COVID share strikingly similar symptom profiles: persistent fatigue, post-exertional malaise, cognitive impairment, unrefreshing sleep, autonomic dysfunction, and widespread pain. Increasingly, research demonstrates that these symptoms arise from overlapping biological disturbances involving systemic inflammation, autonomic dysregulation, endothelial impairment, and disrupted cellular energy production. These processes are thought to reinforce one another, creating a self-sustaining cycle of physiological stress that maintains chronic illness.
Whole-Body Cryotherapy (WBCT) offers a biologically plausible intervention that can interrupt these pathological loops. Brief exposure to extreme cold triggers a rapid multisystem response across neurovascular, immune, and metabolic pathways. Evidence suggests that WBCT enhances autonomic balance, improves microvascular function through vasoconstriction-vasodilation cycling, reduces oxidative stress, and stimulates anti-inflammatory signalling. Preliminary clinical work, including studies in ME/CFS, shows reductions in fatigue, improved cognitive clarity, and better autonomic regulation following multi-session cryotherapy. Early mechanistic findings, such as changes in blood-brain barrier proteins like claudin-5, further support WBCT's potential to modulate barrier integrity and downstream neuroimmune activity.
The present study is therefore designed as a pilot feasibility investigation to determine whether a fully powered mechanistic trial is achievable. The protocol includes four groups: healthy controls, ME/CFS, Fibromyalgia, and Long COVID each completing ten WBCT sessions over two weeks, with comprehensive pre- and post-intervention assessments.
Central to this study is establishing whether recruitment, retention, and completion of intensive multidimensional outcome measures are practical within this population. Alongside feasibility assessment, the study will explore changes in symptom burden using validated clinical surveys, and will collect objective data on sleep, physical activity, and mitochondrial and immunometabolic function through biospecimens. These exploratory measures will provide essential estimates of variability, acceptability, and sensitivity to change, all of which are required to refine the design of a future randomised controlled trial.
The multi- \& trans-disciplinary integration of patient-reported outcomes, wearable-derived physiological data, and advanced cellular and molecular assays provides a coherent mechanistic framework for understanding WBCT's multisystem effects. If participants can be successfully recruited, retained, and assessed, the findings will offer both practical and scientific justification for progression to a larger, definitive study capable of evaluating therapeutic efficacy.
255 studies on the registry are indexed under Fatigue Syndrome, Chronic; 59 are open to participants now.
This study's planned enrollment of 40 is below the median of 60 across 171 interventional studies indexed under Fatigue Syndrome, Chronic.
Browse Fatigue Syndrome, Chronic studies →Oxford Brookes University is the lead sponsor of 35 studies on the registry; 6 are open to participants now.
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The relatively small group size is appropriate for a pilot feasibility study, where the primary aim is to assess recruitment, retention, tolerability of the intervention, and the practicality of completing the proposed outcome measures.
The sample size reflects the exploratory nature of the study, current resource availability and funding, and the intensive intervention schedule requiring ten visits over a two-week period. In addition, there is limited UK-based evidence regarding participant responses to whole-body cryotherapy within these clinical populations, further supporting a cautious, feasibility-focused sample size.
Exclusion Criteria:
10 sessions administered over 2 consecutive weeks. Sessions will be conducted in an indirect liquid nitrogen-cooled cryochamber with a prechamber set at -60∘°C and a main chamber at -120∘°C. To maximise safety and tolerability in this sensitive patient population, the protocol features a gradual increase in exposure time. Following a 30-second familiarisation session (sessions 1 \& 2), exposure time in the main chamber will increase incrementally from 1 minute on day 1 to a maximum of 3.5 minutes on day 10
Device: Cryotherapy
Intervention: Whole-body cryotherapy intervention consists of 10 sessions administered over 2 consecutive weeks. Sessions will be conducted in an indirect liquid nitrogen-cooled cryochamber with a prechamber set at -60∘°C and a main chamber at -120∘°C. To maximise safety and tolerability in this sensitive patient population, the protocol features a gradual increase in exposure time. Following a 30-second familiarisation session (sessions 1 \& 2), exposure time in the main chamber will increase incrementally from 1 minute on day 1 to a maximum of 3.5 minutes on day 10. Participants will wear standardised protective clothing (gloves, socks, headband, and mask) during all sessions.
Feasibility outcome measurements
recruitment and retention, whereby targets for each are set at 20% and 80%, respectively
Time frame: Change pre to post intervention (2-weeks)
Short-form 36
The SF-36 assesses health-related quality of life across eight domains. Scores range from 0 to 100 for each domain, with higher scores indicating better health and quality of life.
Time frame: Change between pre and post intervention (2-weeks)
EQ-5D-5L - Health-related quality of life
The EQ-5D-5L assesses health-related quality of life across five dimensions, each scored from 1 (no problems) to 5 (extreme problems). Higher scores indicate greater health problems. The EQ visual analogue scale ranges from 0 (worst imaginable health) to 100 (best imaginable health).
Time frame: Change between pre and post intervention (2-weeks)
Fatigue Symptom Survey
The Fatigue Symptom Survey assesses the severity and characteristics of fatigue symptoms. Higher scores indicate greater fatigue severity.
Time frame: Change between pre and post intervention (2-weeks)
Chalder Fatigue Scale
The Chalder Fatigue Scale assesses physical and mental fatigue. Scores range from 0 to 11 using the bimodal scoring method, with higher scores indicating greater fatigue.
Time frame: Change between pre and post intervention (2-weeks)
Fatigue Impact Scale
The Fatigue Impact Scale assesses the impact of fatigue on physical, cognitive, and psychosocial functioning. Scores range from 0 to 160, with higher scores indicating a greater impact of fatigue on daily functioning.
Time frame: Change between pre and post intervention (2-weeks)
Epworth Sleepiness Scale
The Epworth Sleepiness Scale assesses daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness. A score of 11 or above indicates excessive daytime sleepiness.
Time frame: Change between pre and post intervention (2-weeks)
COMPASS-31
The COMPASS-31 assesses symptoms of autonomic dysfunction across multiple autonomic domains. Scores range from 0 to 100, with higher scores indicating greater autonomic symptom burden.
Time frame: Change between pre and post intervention (2-weeks)
Barthel Index
The Barthel Index assesses independence in activities of daily living. Scores range from 0 to 100, with higher scores indicating greater independence and lower scores indicating greater dependence.
Time frame: Change between pre and post intervention (2-weeks)
Near Infrared Spectroscopy (NIRS) - Mitochondrial functioning
NIRS will assess skeletal muscle oxygenation and haemodynamic responses as indicators of mitochondrial and muscle oxidative function. Outcomes will be reported as changes in NIRS-derived measures from baseline, with the direction of change interpreted according to the specific parameter assessed.
Time frame: Change between pre and post intervention (2-weeks)
Physical Activity and Sleep - Wrist-worn tri-axial accelerometer
A wrist-worn tri-axial accelerometer (Axivity AX3) will objectively assess physical activity and sleep. Outcomes will include measures such as daily activity levels, sedentary time, sleep duration and sleep-related parameters. Higher physical activity values indicate greater activity, while higher sedentary time indicates greater sedentary behaviour.
Time frame: Change between pre and post intervention (2-weeks)
Blood, urine, stool and saliva - Biomarker and multi-omic analyses
Blood, urine, stool and saliva samples will be collected for biomarker, multi-omic and cellular analyses. Outcomes will include measures of gut barrier integrity, immune function, bioenergetics, plasma and gut metabolomics, and gut microbiome composition. Individual biomarkers and molecular measures will be reported according to their validated assay-specific units and direction of change.
Time frame: Change between pre and post intervention (2-weeks)
Plan to share: Yes — De-identified individual participant data supporting the published results may be made available to qualified researchers upon reasonable request, subject to review by the study team and appropriate ethical, governance and data protection requirements. Data will not be made publicly available as a complete dataset. Any data shared will be limited to that necessary to address the approved research question and will be consistent with participant consent and applicable regulations.
Supporting information: Study protocol, Informed consent form, Clinical study report
Time frame: IPD and supporting information will be available following publication of the primary study results. Data will remain available for a reasonable period thereafter, subject to ethical, governance and data protection requirements (set at 10 years post completion).
Access criteria: Access to de-identified individual participant data and supporting information will be restricted to qualified researchers with an appropriate scientific justification and an approved research proposal. Access will be limited to the data necessary to address the approved research question and will exclude directly identifiable information. Particular consideration will be given to the re-identification risks associated with high-dimensional clinical, imaging and multi-omic datasets. All data sharing will be subject to appropriate ethical, governance, data protection and information security requirements, including relevant institutional approvals and, where applicable, Human Tissue Act requirements and Material Transfer Agreements. Data will be transferred and stored using secure, institutionally approved systems, with controlled access and appropriate data-sharing agreements. Requests will be reviewed by the study team before access is granted.
Data sharing details ↗ · www.brookes.ac.uk
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Jan 2027, 3 months later.
Of 69 non-industry interventional studies with no phase under Fatigue Syndrome, Chronic, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 43. This study's planned 3 months is below that.
Counting every sponsor, half of 74 studies reached it within 23 months; a quarter within 11 and three quarters within 38.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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