BFR Training Contraindications: What the Evidence Says (2026)

By Purpose with Presence FitnessUpdated November 6, 202610 min read

Quick answer: No source we read gives one agreed list of BFR training contraindications. They give general clotting risk factors, pregnancy as a clotting risk, rare adverse events, common minor side effects and a call for caution about the heart. The NHS says to speak to a GP first if you have medical conditions. Ask a clinician before starting.

This page has no affiliate links. Elsewhere in our fitness guides we are an independent affiliate of the training programs we link and earn a commission on purchases. This article is not medical advice; consult a qualified professional before starting any training program, and before blood flow restriction training in particular.

This page is the safety companion to our blood flow restriction training beginner guide. It reports what a small set of papers and one public health page say. It gives no dosage and cannot tell you whether BFR is safe for you; only a clinician who knows your history can.

Is there an agreed list of BFR contraindications?

Not in the sources we read. None of them issues a single list of people who may never use BFR, and none issues a checklist that clears someone to start. What they give us is a set of separate pieces:

These are general clotting (VTE) risk factors that a 2019 review lists as background risks, pregnancy as that review states it, rare adverse events counted in a 2020 systematic review, side effects from practitioner surveys, a cardiovascular concern raised in 2015, and NHS advice to speak to a GP before exercise in general.

A 2026 narrative review for strength and conditioning coaches, Gaviglio, Cook and Bird (2026), says risk stratification systems "can effectively identify absolute and relative contraindications requiring medical clearance prior to BFR use." The abstract we read does not print the list itself, so we do not invent one. It is written for coaches working with athletes, not for the general public.

The public health baseline is simpler. The NHS page on physical activity guidelines for adults aged 19 to 64 says: "Speak to your GP first if you have not exercised for some time, or if you have medical conditions or concerns." The NHS page does not mention BFR. We cite it as general advice before starting any exercise, and this article makes no claim that it covers BFR.

What clotting risk factors does the 2019 review list?

The longest safety discussion on our reading list is Patterson et al. (2019), a review and guidelines paper on BFR methodology, application and safety. It was corrected after concerns about the phrase "Position Stand" in its title, and it is not a position stand.

In its introduction the paper lists general venous thromboembolism (VTE) risk factors, meaning factors linked to blood clots in the veins. It cites these from other work as background risks in the wider population. They are not a BFR screening checklist that the paper issues, and we do not present them as one. Here is what the review says, in its own words:

• Medical conditions "such as major orthopedic surgery, major general surgery, lower extremity paralysis due to spinal cord injury, pelvic, hip or long bone fractures, poly-trauma and cancer".
• "Additional risk factors include a history of prior VTE, obesity, immobility, oral contraceptives, family history of VTE, physical inactivity and genetic conditions that affect blood clotting".
• "Pregnancy carries an elevated risk both in the perinatal and post-natal periods".

The same paper reports that "the totality of the literature reveals minimal adverse events pertaining to VTE and clinically reported events have not been reported." It also notes that "Many of the published BFR-RE trials do not directly measure for VTE formation or use diagnostic imaging." Many trials were not built to look for clots. Neither statement says a given person is safe.

Pregnancy

The review names pregnancy as a period of elevated clotting risk, both around birth and after it. It is a general statement about VTE, not a BFR trial in pregnant people. Our own precaution is to ask a clinician before any BFR session if you are pregnant or recently gave birth, and the sources give us no basis to say more.

How common are serious adverse events?

Rare, in the studies reviewed, but not absent. Minniti et al. (2020) pooled the evidence on BFR as a therapeutic intervention for people with musculoskeletal disorders. The abstract reports that "Nineteen studies met eligibility criteria, with a pooled sample size of 322." Of those studies, "Nine studies reported no adverse events, while 3 reported rare adverse events, including an upper extremity deep vein thrombosis and rhabdomyolysis." It adds: "Three case studies reported common adverse events, including acute muscle pain and acute muscle fatigue."

The counts the abstract gives are: overall, 14 of 322 people; rare events, 3 of 322 overall, 3 of 168 in the BFR groups and 0 of 154 in the control groups; any adverse event, 10 of 168 with BFR and 4 of 154 in controls. In the randomized controlled trials, "individuals exposed to BFRT were not more likely to have an adverse event than individuals exposed to exercise alone."

The population was people with musculoskeletal disorders, and the authors conclude only that BFR "appears to be a safe strengthening approach for knee-related musculoskeletal disorders, but further research is needed to make definitive conclusions." They also say "further research is needed to effectively screen who might be at risk for rare adverse events." The three rare events all sat in the BFR groups. Small numbers cannot rule out a real difference, and a pooled sample of 322 cannot speak for everyone.

The rhabdomyolysis note

Rhabdomyolysis is a breakdown of muscle tissue. Patterson et al. (2019) write that "there are isolated case reports of rhabdomyolysis occurring through the use of BFR-RE" and that, from their analysis of the published literature, "the risk remains very low (0.07-0.2%)". Their conclusion is that "evidence does not currently suggest that the risk is inflated compared to traditional exercise." The passage we read does not state what the percentage is out of.

The review also says exertional rhabdomyolysis cases "are typically associated with an exercise load that greatly exceeds the fitness and normal physical exertion of the participant." That sentence says nothing about a first BFR session feeling harder.

What side effects do practitioners report?

Side effects are more common than serious events, and they are mostly minor. Patterson and Brandner (2018) surveyed practitioners. The abstract says "data were obtained from 250 participants, with 115 stating that they had prescribed BFR as an intervention." It gives these figures: "The incidence rate of side effects was largest for delayed onset muscle soreness (39.2%), numbness (18.5%), fainting/dizziness (14.6%) and bruising (13.1%)." The abstract does not say what the percentages are out of.

This is a questionnaire, not a measured trial. The authors close with a plain line: "care should be taken to ensure that practice matches current research to ensure the safety of this technique."

A 2025 survey of physical therapists reports a lower rate. Weatherholt et al. (2025) had "134 licensed PTs from 20 states" complete the survey. They report "No major adverse effects reported (e.g., thrombosis, rhabdomyolysis, nerve damage)", and that minor effects, "including dizziness, numbness, nausea, and delayed onset muscle soreness, were reported by 8% of participants (n = 11)." These respondents were licensed clinicians, which is a different setting from training alone at home. Only physical therapists currently using BFR were surveyed, so people who stopped using it are not counted.

The 2026 narrative review by Gaviglio, Cook and Bird adds that "adverse events are transient and non-serious, while serious events appear rare when evidence-informed protocols are applied." The claim is tied to evidence-informed protocols, not to any use of any band. Our page on how tight BFR bands should be covers what the research says about pressure, and why you cannot judge it by feel.

Why do some researchers urge more caution on the heart?

Spranger et al. (2015) published a paper titled as a "call for concern". Their worry is the exercise pressor reflex, a cardiovascular response driven by the working muscles, and what BFR might do to it. They note that this reflex is exaggerated "in disease states such as hypertension (HTN), heart failure (HF), and peripheral artery disease (PAD)", and that "concerns are raised that BFR training can be used safely for the rehabilitation of patients with cardiovascular disease". In the authors' framing, "Abnormal BFR-induced and EPR-mediated cardiovascular complications generated during exercise could precipitate adverse cardiovascular or cerebrovascular events (e.g., cardiac arrhythmia, myocardial infarction, stroke and sudden cardiac death)."

They go further and say "even normal, healthy individuals performing resistance training exercise with BFR are potentially at increased risk for deleterious cardiovascular events." And they argue that "A more complete understanding of the consequences of BFR training is needed before this technique is passively explored by the layman athlete or prescribed by a health care professional."

Because the authors raise the possibility for healthy people too, this is a call for research, not a screening rule, and not a trial that measured heart events. Other sources here report few serious events, and we cannot settle that tension.

Our precaution: when should you ask a clinician before trying BFR?

This list is ours. We built it from the sources above, and none of those sources issues these as BFR rules. It is a prompt for a conversation, not a screening tool, and not a test you can pass or fail on your own. Each line says where the concern comes from.

• You have had a blood clot before, or you have any of the general clotting risk factors in the 2019 review. Source: Patterson et al. (2019), which lists them as general VTE background risks and does not itself issue a BFR rule.
• You are pregnant or recently gave birth. Source: Patterson et al. (2019), which says pregnancy carries elevated clotting risk; it does not itself issue a BFR rule for pregnancy.
• You have a cardiovascular disease such as hypertension, heart failure or peripheral artery disease. Source: Spranger et al. (2015), whose authors raise a concern and call for research; it is not a screening rule.
• You have a musculoskeletal condition and are weighing BFR. Source: Minniti et al. (2020), which only studied people with musculoskeletal disorders and says research is still needed to screen who might be at risk for rare events; it issues no rule.
• You have not exercised for some time, or you have medical conditions or concerns. Source: NHS: "Speak to your GP first." The page is about exercise in general and does not mention BFR.
• You want to know whether you fall into an absolute or relative contraindication group. Source: Gaviglio et al. (2026), who say screening systems identify these; the abstract does not give the list.
• You get fainting, dizziness, numbness or unusual bruising. Source: Patterson and Brandner (2018), who list these as reported side effects; the paper does not set a stopping rule in the abstract we read.

If none of those apply, the sources still do not say you are cleared.

How does this connect to the results research?

Safety only matters next to benefit. Our summary of what the BFR training results research shows lays out the effect sizes, the populations and the certainty. Weigh the two pages together, with the largest uncertainty in people the trials did not recruit, and take the question to a clinician rather than decide alone.

Our fitness program comparison hub links the other guides. Nothing in these sources makes BFR compulsory.

Primary sources

• Patterson SD et al. (2019). Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Frontiers in Physiology.
• Minniti MC et al. (2020). The Safety of Blood Flow Restriction Training as a Therapeutic Intervention for Patients With Musculoskeletal Disorders: A Systematic Review. American Journal of Sports Medicine.
• Patterson SD, Brandner CR (2018). The role of blood flow restriction training for applied practitioners: A questionnaire-based survey. Journal of Sports Sciences.
• Weatherholt AM et al. (2025). Blood Flow Restriction Use by U.S. Physical Therapists: A Survey on Settings, Equipment, and Adverse Effects. International Journal of Exercise Science.
• Gaviglio C, Cook CJ, Bird SP (2026). Blood Flow Restriction in Athletic Populations-Part 1: Safety Considerations, and Methodological Frameworks. Journal of Functional Morphology and Kinesiology.
• Spranger MD et al. (2015). Blood flow restriction training and the exercise pressor reflex: a call for concern. American Journal of Physiology Heart and Circulatory Physiology.
• NHS. Physical activity guidelines for adults aged 19 to 64. nhs.uk.

Frequently asked questions