Is Swimming a More Tolerable Form of Movement for Individuals With Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome?

NCT07454395 | Suspended

• 2 other identifiers: 30003523n2cx3
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

Individuals with ME/CFS experience profound exercise intolerance and post-exertional malaise. This remote (app-based) pilot study explores whether light, fully self-paced, swimming may be a tolerable form of movement for people with ME/CFS and related conditions, due to the distinct physiological effects of water immersion. The horizontal posture and hydrostatic pressure of water supports venous return and reduces orthostatic stress, while cool water exposure may influence autonomic and inflammatory responses. We are recruiting adults with mild-to-moderate ME/CFS and related conditions for this study examining short-term symptom and autonomic responses to gentle swimming. Participants will choose their own intensity and duration and may stop at any time. A light cycling session is available as an optional comparator for those who feel comfortable doing so. \[Note: this is not an exercise training or rehabilitation study, and participation is only intended for individuals who can tolerate some gentle activity and can be in public spaces without triggering post-exertional malaise. You should be comfortable with swimming, but flotation or other assistive devices are welcome\]

Conditions

ME/CFS; Long COVID; Post- COVID-19 Syndrome; POTS - Postural Orthostatic Tachycardia Syndrome; Fibromyalgia; Overtraining Syndrome; Post-Viral Fatigue Syndrome; Mast Cell Activation Syndrome

Keywords

swimming; ME/CFS; HRV; Visible App; long-covid

Outcome Measures

Primary Outcomes (2)

• Symptoms

  Daily symptoms will be recorded in the Visible app each evening as part of the evening check-in. All available symptoms listed on the app will be evaluated (44 items, rated 0-3, with 0=none, and 3= severe). The total score will be the sum of all 44 items.

  From enrollment until minimally three days post final exercise session (11~15 days total)

• Heart Rate Variability

  HRV will be collected each morning upon waking, and in the seated-upright position, through the Visible application. This is assessed with lnRMSSD plotted on a 0-100 scale. Analyses will focus on changes in HRV from baseline to 24, 48, and 72 hours post-swim session compared to post-bike session.

  From enrollment until minimially three days after one or both exercise sessions (11~15 days total)

Secondary Outcomes (3)

• Time to recovery

  From enrollment to the post-exercise recovery periods from days ~9-11 and ~13-15.

• Exercise Load

  Exercise days ~8 and ~12.

• Severity of ME/CFS

  Baseline

Study Arms (2)

ME/CFS group

EXPERIMENTAL

Individuals with ME/CFS and related conditions

Behavioral: Swimming; Behavioral: Cycling

Control Group

ACTIVE COMPARATOR

Healthy age and sex matched controls

Behavioral: Swimming; Behavioral: Cycling

Interventions

Swimming BEHAVIORAL

Following a week of baseline HRV and symptoms tracking, all participants will be asked to perform a light swimming session. This session should be at a self-selected intensity and duration, however it should always be performed at an intensity that is under a rating of perceived exertion of 5/10 (easy to moderate at most). Recommended duration is \~15-30 min. Participants may use flotation or assistive devices as they wish. Cool water is recommended.

Control Group; ME/CFS group

Cycling BEHAVIORAL

After a minimum of three days of recovery following swimming, and once the visible application indicates a stable recovery score of at least 4/5 (and the participant feels okay), they may optionally complete a cycling session on a stationary bike. This biking session will also be at a self-selected duration and intensity (effort \<5/10), which does not need to match the first session. If participants feel that they are unable to complete the biking exercise session, they can still participate in the study and only complete the swimming. If they believe that it would exacerbate symptoms and cause harm, they should not do the biking.

Control Group; ME/CFS group

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Be between the ages of 18-80
• Meet the criteria of (ME/CFS). The diagnostic criteria for ME/CFS according to the primary Canadian Consensus Criteria are: 1. Fatigue (significant physical and mental fatigue that is new onset, unexplained, persistent or recurrent, and substantially reduces activity level), 2. Post-exertional malaise and/or post-exertional fatigue (general feeling of discomfort, weakness and/or fatigue, and potentially worsening associated symptoms, following physical or mental exertion; slow recovery which is usually longer than 24 hours), 3. Sleep dysfunction (unrefreshing sleep or disturbances in sleep quantity or rhythm), and 4. Pain (significant degree of muscle and/or joint pain, and/or significant headaches of new type, pattern or severity). This may include individuals with (but not limited to) Post-Viral Fatigue Syndrome, Long-Covid 19, Overtraining Syndrome (OTS), and/or co-occurring Postural Orthostatic Tachycardia Syndrome (POTS), Fibromyalgia, and/or Mast Cell Activation Syndrome (MCAS).
• Experience some degree of post exertional malaise and have some degree of exercise intolerance upon physical exertion.
• Must have been previously physically active and be able to swim
• Must be considered moderate-to-mild CFS (not severe or very severe) with a FUNCAP27 score between 3.0-5.8.
• Must be able to do some light physical activity and go to public places without causing post-exertional malaise.

You may not qualify if:

• Individuals with cardiovascular, pulmonary, metabolic, renal, endocrine, autoimmune, neurological, inflammatory condition, infectious disease, or mental illness that makes exercise participation a risk will be excluded from the study.
• Individuals who are pregnant will be excluded from the study.
• Individuals with musculoskeletal injuries that prevent exercise participation will be excluded from the study
• Be between the ages of 18-80
• Must be physically active and be able to swim.

Sponsors & Collaborators

• Simon Fraser University: lead

Study Sites (1)

Simon Fraser University

Burnaby, British Columbia, V5A 1S6, Canada

Location

Related Publications (6)

• Arron HE, Marsh BD, Kell DB, Khan MA, Jaeger BR, Pretorius E. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: the biology of a neglected disease. Front Immunol. 2024 Jun 3;15:1386607. doi: 10.3389/fimmu.2024.1386607. eCollection 2024.

  PMID: 38887284 BACKGROUND

• Kooshki M, Rezeai-Farimani R, Moradpour A, Baradaran Rahimi V, Askari VR. How Swimming Modulates Inflammatory Pathways in Pain, Neurodegenerative, and Metabolic Disorders. Brain Sci. 2025 Oct 18;15(10):1121. doi: 10.3390/brainsci15101121.

  PMID: 41154214 BACKGROUND

• Sommerfelt K, Schei T, Seton KA, Carding SR. Assessing Functional Capacity in Myalgic Encephalopathy/Chronic Fatigue Syndrome: A Patient-Informed Questionnaire. J Clin Med. 2024 Jun 14;13(12):3486. doi: 10.3390/jcm13123486.

  PMID: 38930014 BACKGROUND

• Sawyer A, Preston R, Leeming H, Martin-Fuller L, Proal A, Putrino D. Wearable technology in the management of complex chronic illness: preliminary survey results on self-reported outcomes. Front Digit Health. 2025 Oct 8;7:1662255. doi: 10.3389/fdgth.2025.1662255. eCollection 2025.

  PMID: 41132394 BACKGROUND

• Vernon SD, Funk S, Bateman L, Stoddard GJ, Hammer S, Sullivan K, Bell J, Abbaszadeh S, Lipkin WI, Komaroff AL. Orthostatic Challenge Causes Distinctive Symptomatic, Hemodynamic and Cognitive Responses in Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Front Med (Lausanne). 2022 Jun 23;9:917019. doi: 10.3389/fmed.2022.917019. eCollection 2022.

  BACKGROUND

• Joseph P, Pari R, Miller S, Warren A, Stovall MC, Squires J, Chang CJ, Xiao W, Waxman AB, Systrom DM. Neurovascular Dysregulation and Acute Exercise Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Placebo-Controlled Trial of Pyridostigmine. Chest. 2022 Nov;162(5):1116-1126. doi: 10.1016/j.chest.2022.04.146. Epub 2022 May 6.

  PMID: 35526605 BACKGROUND

Related Links

• Lab website

MeSH Terms

Conditions

Fatigue Syndrome, Chronic; Post-Acute COVID-19 Syndrome; Postural Orthostatic Tachycardia Syndrome; Fibromyalgia; Overtraining Syndrome; Mast Cell Activation Syndrome

Interventions

Swimming

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Encephalomyelitis; Neuroinflammatory Diseases; Nervous System Diseases; Neuromuscular Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; COVID-19; Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases; Post-Infectious Disorders; Orthostatic Intolerance; Primary Dysautonomias; Autonomic Nervous System Diseases; Rheumatic Diseases; Fatigue; Signs and Symptoms; Mast Cell Activation Disorders; Immune System Diseases

Intervention Hierarchy (Ancestors)

Locomotion; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise; Motor Activity

Study Officials

• Alexandra Coates, PhD

  Biomedical Physiology and Kinesiology, Simon Fraser University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: This is non-randomized cross-over design. A healthy age and sex matched control group will perform the same intervention to understand the healthy response to the interventions.

Study Record Dates

• First Submitted: February 25, 2026
• First Posted: March 6, 2026
• Study Start: February 20, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: March 30, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)