TL;DR: Cancer-related fatigue is a persistent, debilitating exhaustion that affects up to 90% of cancer survivors during treatment and approximately one third long after treatment ends. Unlike ordinary tiredness, it is not relieved by rest. Hyperbaric oxygen therapy (HBOT) has been studied as a potential intervention for persistent fatigue in cancer survivors, with some evidence showing symptom improvement particularly in patients whose fatigue is linked to radiation injury or chronic inflammation. This Daffodil Month, we explore what cancer-related fatigue is, what the current research says about HBOT, and what Canadian patients need to know.
Estimated reading time: 10 minutes
What Is Cancer-Related Fatigue?
Cancer-related fatigue (CRF) is a distressing, persistent sense of physical, emotional, and cognitive tiredness that is not proportional to recent activity and interferes with usual functioning. It is one of the most common and under-treated symptoms in cancer patients and survivors, and fundamentally different from everyday tiredness.
Key features that distinguish cancer-related fatigue from ordinary fatigue include:
- Not relieved by rest or sleep – sufferers wake up feeling as exhausted as when they went to bed
- Disproportionate to exertion – small tasks produce overwhelming exhaustion
- Interferes with daily functioning – work, relationships, and basic self-care become difficult
- Persists for months or years after active treatment ends
- Affects physical, mental, and emotional energy – often described as a full-body depletion
According to Hofman et al. (Oncologist 2007; PMID 17573451), up to 90% of patients treated with radiation and up to 80% of those treated with chemotherapy experience fatigue, and approximately one third continue to experience it for months or years after treatment concludes. During Daffodil Month, it is important to recognise that fatigue is not a minor inconvenience – it is a major factor in survivorship quality of life.
What Causes Cancer-Related Fatigue?
Cancer-related fatigue has multiple overlapping causes, which is why it can be so difficult to treat:
| Cause Category | Mechanism | Example |
|---|---|---|
| Treatment effects | Direct damage to healthy cells, bone marrow suppression | Chemotherapy anaemia, radiation tissue damage |
| Chronic inflammation | Elevated cytokines cause sickness-behaviour fatigue | Persistent elevated IL-6, TNF-alpha after treatment |
| Mitochondrial dysfunction | Impaired cellular energy production | Reduced oxidative phosphorylation in muscle and brain cells |
| Hypoxia in damaged tissue | Radiation-injured tissue becomes chronically oxygen-starved | Chronic fatigue after pelvic or chest wall radiation |
| Anaemia | Reduced oxygen-carrying capacity of blood | Chemotherapy-induced anaemia, chronic disease anaemia |
| Sleep disruption | Poor sleep quality from pain, anxiety, medications | Insomnia, fragmented sleep |
| Depression and anxiety | Mental health overlap with fatigue | Treatment-related mood disorders |
Because cancer-related fatigue has multiple causes, effective treatment typically requires addressing several of these pathways simultaneously. Standard interventions include graded exercise, cognitive behavioural therapy, sleep hygiene improvements, and treatment of underlying anaemia or mood disorders.
How Might HBOT Address Cancer-Related Fatigue?
The biological rationale for HBOT in cancer-related fatigue involves several of the mechanisms above:
- Increased oxygen delivery to damaged tissues: HBOT floods the body with dissolved oxygen, potentially improving function in tissue that has been rendered hypoxic by radiation or chronic inflammation
- Anti-inflammatory effects: HBOT has been shown to modulate the inflammatory cascade and reduce levels of pro-inflammatory cytokines that contribute to sickness-behaviour fatigue
- Mitochondrial support: Repeated exposure to elevated oxygen followed by normoxia may trigger mitochondrial biogenesis – the creation of new energy-producing cellular structures
- Angiogenesis: Growth of new blood vessels can restore circulation to areas of chronic tissue damage
- Stem cell mobilisation: HBOT has been shown to mobilise endogenous stem cells, which may support tissue repair
HBOT for cancer-related fatigue is an investigational use. It is not currently among the 14 conditions recognised under Health Canada’s device licensing framework, and it is not covered by provincial health plans for this indication.
What Does the Research Show?
Direct research on HBOT specifically for cancer-related fatigue is limited. Most available evidence comes from studies where fatigue was a secondary outcome in broader research on radiation injury, or from related conditions like post-COVID fatigue.
Evidence from Radiation Injury Studies
A 2022 study examining symptom burden and health-related quality of life six months after HBOT in cancer survivors with pelvic radiation injuries found sustained improvements in multiple quality-of-life domains, including energy levels and physical functioning (Glover et al., 2022).
The 2026 clinically focused review of HBOT for chronic radiotherapy-related adverse effects noted that fatigue often accompanies late radiation tissue injury, and that addressing the underlying tissue damage through HBOT can indirectly improve energy and function (Dejonckheere et al., 2026).
Breast Cancer Lymphoedema and Quality of Life
A 2023 exploratory clinical trial examined HBOT for arm lymphoedema and quality of life after breast cancer. The study reported improvements in patient-reported symptom burden, including fatigue-related measures, alongside the primary lymphoedema outcomes (Breast Cancer Lymphoedema Trial, 2023).
Post-Viral and Chronic Fatigue Evidence
Related research on post-acute COVID-19 fatigue may be informative for cancer-related fatigue, as both conditions share features of chronic inflammation, mitochondrial dysfunction, and persistent exhaustion. A 2025 review explored non-conventional treatments for fatigue in post-acute COVID-19 syndrome, including HBOT, noting emerging evidence for symptomatic improvement (Post-COVID Fatigue Review, 2025).
A 2025 case report documented notable improvements in chronic fatigue symptoms following low-pressure HBOT in a patient with chronic inflammatory response syndrome, suggesting that HBOT may benefit fatigue that has an inflammatory component (Fatigue Case Report, 2025).
Safety Profile
A 2025 safety evaluation of HBOT for managing cancer treatment complications confirmed that the therapy has an acceptable safety profile when delivered by qualified hyperbaric medicine teams in accredited facilities (Safety Evaluation, 2025).
What Are the Limitations of the Current Evidence?
Patients and clinicians considering HBOT for cancer-related fatigue should understand the evidence limitations:
- No large RCT has specifically tested HBOT for cancer-related fatigue as a primary outcome
- Most evidence is indirect, coming from studies where fatigue was measured alongside other outcomes
- Fatigue is multifactorial, so HBOT would likely be one component of a broader management approach rather than a standalone treatment
- Patient selection criteria are not established – which fatigue subtypes respond best is unclear
- Cost-effectiveness in the Canadian healthcare context has not been assessed for this indication
- Response may be gradual – benefits from HBOT often accrue over the full treatment course rather than immediately
Is HBOT for Cancer-Related Fatigue Covered in Canada?
No. Cancer-related fatigue is not currently among the 14 conditions recognised under Health Canada’s device licensing framework for hyperbaric chambers. It is not covered by OHIP, MSP, AHCIP, or any other provincial health insurance plan for this indication.
However, if the fatigue is linked to an underlying condition that IS covered – such as delayed radiation tissue injury – patients may qualify for coverage based on the underlying diagnosis rather than the fatigue itself. This is worth discussing with your oncologist and a hyperbaric medicine specialist.
For provincial coverage details and the list of publicly funded indications, visit the Canada Hyperbarics coverage guide. Fatigue is not among the recognised indications, so discuss any interest in HBOT with your treating oncology team.
What Should Cancer Survivors With Fatigue Do?
If persistent fatigue is affecting your life after cancer treatment, consider these evidence-based steps:
- Talk to your oncology team. Cancer-related fatigue is a recognised clinical condition with multiple management strategies. A formal fatigue assessment can identify treatable causes.
- Rule out reversible causes. Check for anaemia, thyroid dysfunction, vitamin deficiencies (especially B12 and vitamin D), and sleep disorders.
- Ask about physical activity programmes. Graded exercise has strong evidence for reducing cancer-related fatigue, even though it seems counter-intuitive.
- Consider cognitive behavioural therapy. CBT specifically for cancer-related fatigue has solid evidence for persistent symptoms.
- Address mood symptoms. Depression and anxiety commonly overlap with fatigue and are both treatable.
- Discuss investigational options. If standard approaches have not helped and you have persistent fatigue with an inflammatory or radiation-injury component, HBOT may be worth exploring with a qualified hyperbaric medicine specialist.
The Canada Hyperbarics research database contains studies on HBOT across multiple cancer-related conditions. If your oncologist refers you for HBOT for a covered indication, fatigue improvement may occur as a secondary benefit.
Frequently Asked Questions
Is cancer-related fatigue the same as feeling tired?
No. Cancer-related fatigue is a distinct medical condition characterised by persistent exhaustion that is not relieved by rest, is disproportionate to activity, and significantly interferes with daily life. It is recognised in clinical guidelines and merits specific assessment and treatment.
How long does cancer-related fatigue last?
Fatigue during active treatment typically improves within weeks to months after treatment ends. However, approximately one third of cancer survivors experience persistent fatigue that continues for months or years. Some survivors report fatigue lasting a decade or more after treatment.
Can HBOT cure cancer-related fatigue?
HBOT is not a cure for cancer-related fatigue. The evidence suggests it may help some patients, particularly those whose fatigue is linked to radiation tissue injury or chronic inflammation, but large controlled trials specifically for fatigue as a primary outcome have not been completed.
Does HBOT cause or worsen fatigue?
Some patients report feeling tired after HBOT sessions, particularly early in a treatment course. This is usually mild and resolves between sessions. The 2025 safety evaluation confirmed that HBOT does not cause chronic fatigue as an adverse effect.
If I pursue HBOT privately, what should I ask the facility?
Ask whether the facility operates clinical-grade hard-shell chambers, whether sessions are supervised by physicians with hyperbaric medicine training, whether the protocol matches those used in published research (typically 2.0 to 2.4 ATA, 60 to 90 minutes, 30 to 60 sessions), and whether there are published outcomes for your condition.
Where can I find a hyperbaric facility in Canada?
The Canada Hyperbarics directory lists 33 facilities (11 hospital programmes and 22 private clinics) across 9 provinces. Visit the facility directory to search by location. Note that for investigational indications like fatigue, treatment would typically be available only at private facilities on an out-of-pocket basis.
This Daffodil Month, Take Fatigue Seriously
Cancer-related fatigue is one of the most common and most under-treated symptoms of cancer survivorship. If you are struggling with persistent exhaustion after treatment, do not dismiss it as something you just have to live with. Evidence-based interventions exist, and ongoing research continues to explore new options including hyperbaric oxygen therapy.
Talk to your oncology team first. Because HBOT for cancer-related fatigue is investigational and not a Health Canada-recognised indication, the right next step is a conversation with your treating physician rather than self-referral to a clinic. See the approved uses of HBOT and the coverage guide for the indications that are publicly funded in Canada.
This April, in recognition of Daffodil Month, Canada Hyperbarics is dedicated to helping cancer survivors understand and access treatments for the lasting effects of cancer therapy.
References
- Glover M, et al. Symptom burden and health-related quality of life six months after hyperbaric oxygen therapy in cancer survivors with pelvic radiation injuries. 2022. View in Canada Hyperbarics Research Database.
- Dejonckheere CS, et al. Hyperbaric oxygen therapy for chronic radiotherapy-related adverse effects: a clinically focused review. CA: A Cancer Journal for Clinicians. 2026. View in Canada Hyperbarics Research Database.
- Effects of an early intervention with hyperbaric oxygen treatment on arm lymphoedema and quality of life after breast cancer: an explorative clinical trial. 2023. View in Canada Hyperbarics Research Database.
- Beyond the basics: exploring non-conventional treatment for fatigue in post-acute COVID-19 syndrome. 2025. View in Canada Hyperbarics Research Database.
- Case report: Low-pressure hyperbaric oxygen therapy as a potential alternative treatment for chronic inflammatory response syndrome. 2025. View in Canada Hyperbarics Research Database.
- Hyperbaric oxygen therapy for managing cancer treatment complications: a safety evaluation. Medicina. 2025. View in Canada Hyperbarics Research Database.
This content is for informational purposes only and does not constitute medical advice. HBOT for cancer-related fatigue is an investigational use that is not currently recognised under Health Canada’s device licensing framework. Consult your physician or a certified hyperbaric medicine specialist for treatment decisions. Canada Hyperbarics is an independent educational resource and is not affiliated with any specific clinic or manufacturer.