BFR & Safety Concerns

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The eternal question is whether BFR is safe? The simple answer is Yes, particularly with Fit Cuffs®

We recommend to either use our algorithmic pressure at the Fit Cuffs Training App “Calculate Pressure” or a percentage (40-80%) of Limb Occlusion Pressure (LOP) which is term used to control the amount of blood flow that is restricted. LOP can be assessed by the Bluetooth Device, hand-held dopplers or by high quality pulse oximeters.

As a rule of thumb, when unaccustomed to BFR in combination with low-load resistance training, avoid going to failure and use the recommended protocol of 30x15x15x15 reps, at about 20-30% 1RM, with 30-45 s. inter-set rest for only one exercise. This is recommended to avoid unintended muscle damage for your first session of BFR, as gradual exposure to higher pressures (70-80% LOP) and the repeated bout effect is the key for both progression and safety.

When Fit Cuffs is utilized with the proper precautions and safety measures, it is highly effective at augmenting the physiological adaptations to low-load resistance and aerobic training in all populations regardless of age or training status.

Though, there are rare cases where one should not use BFR i.e. absolute contraindications, but in reality, most contraindications are relative, that is why the accumulated amount of frailty for a person is vital.

<strong>That is why, we advise you to consult with your physician before you start using Fit Cuffs if any of the following apply</strong> <strong><strong>⬇</strong></strong>
  • Chronic heart disease
  • Untreated Type 1 or type 2 diabetes – BFR Training should not be used in patients with glucose > 250 mg/dl associated with diabetic retinopathy and diabetic ketoacidosis.
  • Kidney disease
  • Concurrent treatment for cancer, or you’ve recently completed cancer treatment
  • Untreated high blood pressures >140/100
  • Clotting problems or abnormal bleeding problems (coagulation disorders)
  • Cardiac arrhythmias
  • Damaged or chronic veins or arteries
  • BMI> 35
  • Open wounds or stitches in the areas of cuff attachment
  • Severe rejuvenate in the legs
  • Severe functional disorders


  • Varicose veins: Compromised vessels that suggest a weakened venous system. When performing a screening for BFR, it is important to identify if these are present, as it will influence whether or not BFR is applicable.
  • Fibromyalgia
  • Hypochondria
  • Pregnancy
  • Controlled high blood pressures

The more comorbidities someone has, the more likely that BFR is contraindicated, but no actual recommendation can be made, so far, the clinician or physician must decide whether a client should or not do BFR.

The data from a survey (Nakajima, et al. 2016) from 2006 – 2016 in 12827 individual at 232 different facilities, shows that the incidence of side effects or adverse events from BFR had about the same relative risk as conventional exercise.

Most importantly, a thorough patient history and examination before use will help to identify absolute contraindications to BFR. These include history of DVT, Stage III or greater hypertension, higher class arrhythmias, early post-operative period from major surgery, and acute sickness or fever.

When conducting the exercise be aware of the following symptoms:

  • Sensation of numbness
  • Pins and needles
  • Uncomfortable tingling
  • Severe discomfort
  • Lightheadedness or dizziness
  • Hypertension
  • Headache
  • Subcutaneous hemorrhage
  • Cool Feeling in the limbs

Haemodynamics (blood movement) after BFR have shown no evidence of increased risk of thrombosis, when studying possible contraindications.

The cuff should only be placed at the upper arm or upper thigh. We do not recommend to place the cuffs at the forearms or calf as the arteries and nerves are more superficial in these areas and can substantially increases the risk of adverse events.

As described, it is recommended to use a relative occlusion pressure at 40-80% of the individualized LOP / AOP and utilize the principles of graduated exposure to reduce the risks associated with BFR resistance- or Cardio Training.

Additionally, please also consider that higher relative occlusion pressures do not have any additional effect on the main muscular response. Though, be aware that untreated high blood pressure and the sensation of tingling can be a contraindication that the health care provider should pay special attention to.

<strong>The specific cardiovascular responses to Blood Flow Restriction (BFR) Training ⬇</strong>

During exercise, the central and peripheral cardiovascular systems respond to increasing oxygen demand from the muscles.

The effect of BFR on the cardiovascular response rely on the restrictive pressure, training modality (resistance training vs aerobic training), mode of application (continuous or intermittent) and restrictive pressure time.

Previous studies that have used a continuous training protocol where the occlusion pressure is maintained during the interest rest periods and have mostly found increased Heart Rate (HR) and blood pressure (BT) compared to training without occlusion e.g., conventional resistance training. Even though, no higher minute volume during training occurs, because Stroke Volume (SV) decreases in proportion to the increase in HR.

In a review by Cristina-Oliveira et al. 2019, they found evidence for BFR Training increases BT beyond conventional training. Based on the studies examining peak BT values during training protocols, they estimated BFR Training to increase BT by 5-10 mmHg above the expected response to conventional training.
However, the literature is contradictory, as recent studies do not find the same increases in HR and BT, for training protocols with continuous pressure. This could potentially be due to the fact that recent studies use individual LOP to a greater extent as opposed to arbitrary non-individualized pressures used by many of the previous studies. Patterson et al. 2018 found in their study that only 11.5% of previous studies utilized individualized pressures ie, LOP.

Although several previous studies find increases in BT during BFR Training, it is important to emphasize this main finding. Which is parallel with the potential risks associated with acute increase in the cardiovascular response, BFR has been shown to reduce BT in the hours after training and chronically after weeks or months of training with BFR.

This acute vs chronic effect on the cardio vascular system has been explored in other forms of exercise like high-intensity interval training, but has only recently been discovered in BFR Training.

From the existing literature, it can be summarized that higher occlusion pressures induces higher cardiovascular potential risks associated with BFR. People diagnosed with cardiovascular disease are prone to an excessive increase in the sympathetic nervous system during exercise known as the exercise pressor reflex. Attention to this potential complication is warranted, however, this can be addressed by reducing the restrictive pressure, total restrictive time, utilizing intermittent pressure and prominently utilize the principles of graduated exposure


  1. Patterson et al. (2019) Blood Flow Restriction Exercise, Considerations of Methodology Application, and Safety.
  2. Patterson & Brandner (2018) The role of blood flow restriction training for applied practitioners: A questionnaire-based survey.
  3. Wernbom et al. (2020) Commentary: Can Blood Flow Restricted Exercise Cause Muscle Damage? Commentary on Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety.
  4. Burr et al. (2020) Response: Commentary: Can Blood Flow Restricted Exercise Cause Muscle Damage? Commentary on Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety
  5. Yasuda et al. (2016) Use and safety of KAATSU training- Results of a national survey in 2016.
  6. Nakajima et al. (2006) Use and safety of KAATSU training: Results of a national survey.
  7. Nascimento et al. (2019) – Potential Implications of Blood Flow Restriction Exercise on Vascular Health.
  8. Christina-Oliveira et al. (2019) Clinical safety of blood flow-restricted training. A comprehensive review of altered muscle metaboreflex in cardiovascular disease during ischemic exercise.
  9. Wernbom et al. (2019) Risk of Muscle Damage With Blood Flow–Restricted Exercise Should Not Be Overlooked.
  10. Cezar et al. (2016) Effects of exercise training with blood flow restriction on blood pressure in medicated hypertensive patients.
  11. Heitkamp (2015) Training with blood flow restriction. Mechanisms, gain in strength and safety.
  12. Loenneke (2011) Potential safety issues with blood flow restriction training.
  13. Nakajima et al. (2011) Key considerations when conducting KAATSU training.
  14. Wernbom et al. (2011) Contractile function and sarcolemmal permeability after acute low-load resistance exercise with blood flow restriction.
  15. Loenneke et al. (2014) Does blood flow restriction result in skeletal muscle damage? A critical review of available evidence.
  16. Kacin et al. (2015) Saftety Considerations With Blood Floow Restricted Resistance Training.

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