Blood Flow Restriction in Older Adults

Background

Frequently, new interventions enter the realm of physical therapy, and patients and therapists alike rush to integrate them. The novelty offers hope, a change of pace, and potentially new benefits. This is particularly noticeable in the rise of interventions such as Graston, and Dry Needling, which have become popular and even common names amongst patients, physicians, and therapists. Another intervention experiencing a meteoric rise in the past 10 years has been Blood Flow Restriction (BFR) exercise. Initially, I had some passing familiarity with BFR from my power lifting and weight lifting experience, but had not considered its effects in rehab.

As with all things, there may be a rush to integrate it with therapy, but it may not work for all populations or all ages, or even the same diagnosis. In particular, Jon Hacke asked me if BFR was safe and effective in older adults. There’s good to moderate evidence of BFR being effective post-surgery ACL rehab to support reduced swelling, increased self efficacy, and increased strengthening earlier on in rehab.¹ However, with the metabolic and musculoskeletal changes that occur as we age, there is the curiosity if something effective and safe in relatively healthy, younger individuals can also be applied in older populations.

 

Statement of Need

As adults age, there is a tendency towards inactivity that results in a loss of maximum explosive power and strength, reducing their ability to respond to sudden losses of balance or meet the demands of daily living.² For every decade after the age of 30, an estimated 3-8% of muscle strength and endurance is lost with inactivity.³ This loss of strength is the result of a changing metabolism as well as daily activities, but it can be attenuated with resistance training.³ The health benefits of resistance exercise are especially to older adults, as it can attenuate muscle loss, bone loss, and has protective effects against diabetes, and over all causes of mortality.^2,3 However, resistance training in older adults can pose novel difficulties, as many may be returning to exercise post-surgery, or with levels of frailty that make traditional resistance training too difficult to demonstrate hypertrophy and strength gains. The LIFTMOR trials clearly demonstrated the safety and efficacy of high load resistance training, but largely amongst healthy adults with no injuries.⁴ However, not every adult may be able to safely function at such a high level immediately. High intensity training may not be tenable due to potential cardiac issues, osteoporotic conditions, or advanced sarcopenia, or simply lack of training with resistance training. The LIFTMOR trials, while successful, spent 4 weeks training their participants in traditional lifting technique and form, and monitored their participants for over 8 months to insure proper form.⁴

Blood Flow Restriction combined with low load exercise is a novel intervention that has risen in popularity in the last decade because of its ability to demonstrate comparable strength and hypertrophy gains with high load intensity training.^5,6 Rather than having to train at 70-80% 1 RM, BFR allows individuals to train at 20-30% 1RM while still gaining hypertrophic and strength benefits. While there is an abundance of data concerning the usefulness of BFR in younger individuals and athletes, such data cannot necessarily be applied to older adults because of their differences in physiology and potential comorbidities. Thus, separate data about concerning the safety and efficacy of BFR when combined with low load resistance training in older adults must be collected. Ideally, it should be data collected on patients similar to those what will be seen in clinic, with a wide range of comorbidities including higher BMIs, hypertension, or high cholesterol. This data is necessary for physical therapists to identify the relevancy, safety, and appropriateness of the intervention for their patients.

 

Overview & Purpose

The purpose of this project was to assess the current literature on combining low-load exercise (approximately 20-30% of 1 repetition maximum) with blood flow restriction exercise, and its effects on strength, hypertrophy, functional outcomes, and quality of life, and determine if BFR is relevant to strength and conditioning in the older adult. This information would be collated such that 1st and 2nd year DPT students would have a reference upon encountering it in the clinic, and be able to apply it with relevance. To achieve the primary goal of this project, data had to be gathered on the expected strength and hypertrophy outcomes given a certain regimen, particularly when compared with standard resistance training. An important part of this project was not only assessing the efficacy, but also the safety of BFR in older adults. As such, the project looked for any adverse events or potentially negative effects that should act as precautions or contraindications. In the final stages of the project, determining the relevancy of BFR when comparing it to other outcomes became important as well. In other words, this project sought to determine the “What, how, and why” of BFR in older adults.

An unexpected difficulty with this project was coming to the conclusion that there is no standard regimen for BFR in older adults. The occlusion pressure, the location of the cuff, and even the tools used to monitor occlusion pressure are all varied. Exercise frequency, duration, and even duration of session and occlusion varied. Part of the project expanded to determine standard occlusion pressure and frequency of treatment to correlate with expected outcome.

 

Products

The products of this project was a power point presentation to the 1st year students via zoom, which was recorded. Given the nature of going through the literature, and pulling out outcomes to determine averages, there was also an excel sheet in which outcomes were compiled.

Recorded Lecture Presentation

BFR Presentation JJ Slides 4.8.21

BFR in Older Adults

Debby, you said it wouldn’t open for you; here’s another version.  BFR in Older Adults

Presentation Evaluation Form(1)

Evidence Table and associated research paper: Blood Flow Restriction in Older Adults Paper

 

Results & Discussion

In adults over 50, a BFR training program operating at 50% occlusion pressure, or 150 mmHg meeting 2-3x week for 8-12 weeks can expect strength gains of approximately 27.4% increase in 1RM, while High Load programs can expect an average of 40.6% in the same time frame. Both high load and BFR programs can expect a 6-10% increase hypertrophy. However, BFR-LL training in the literature currently has little to no impact on functional outcomes. This emphasizes that while increases in strength and muscle size are positive, they do not always correlate directly to functional training; performing knee extensions and leg curls do not necessarily correlate to improved squatting or reaching because they isolate relevant lower extremity muscles from coordinating with the core and upper extremities. Perhaps future BFR literature will utilize occlusion while performing more functional activities.

An unexpected conclusion from this project was that BFR-LL may have negative effects on the neuromuscular control. The only adverse event identified by this project was a 5% decrease in Maximum Voluntary Contraction (MVC) acutely following a BFR-LL intervention.⁷ Two other studies identified that the neurological strength gains that occur in the first 6 weeks are delayed, and manifested in the last 6-12 weeks of the training program.⁸ These data combined suggest that BFR changes an individual’s ability to maximally contract, and actively recruit muscle fibers. This could put individuals performing BFR exercise at higher risk for postural instability, or reduced responsiveness during dynamic tasks.

An important conclusion from this project is that BFR-LL training is comparable to high load training in older adults, and is largely safe. However, we must consider the context of BFR, and its contraindications. For example, BFR is contraindicating in individuals with hypertension, high cholesterol, diabetes, a high BMI, recent fractures, active infections, or wounds. Unfortunately, that rules out the majority of patients that we will see in clinic, and if they lack those comorbidities, odds are low these older adults will be seeking therapy in the first place. Additionally, the expensive, logistical difficulty, and discomfort of BFR are also important considerations. Occlusion cuffs can range from $50 to over $1000, and also require a concurrent monitoring device such as a doppler to insure pressure is high enough to promote changes, but not so high as to be damaging. Each session, time must be dedicated to donning and doffing the cuff, setting up the patient on the equipment, managing the lines, as well as checking and maintaining the cuff pressure throughout. In a physical therapy clinic with 30 minute appointment slots, such a time consuming intervention may not be the most efficient use of time. Lastly, BFR is uncomfortable, and many individuals complain or even dislike the cuffs. As such BFR may have poor patient compliance. Given the fact that BFR has comparable benefits as high load training in older adults, but has numerous contraindications, additional logistic complications, and is uncomfortable, BFR may prove to be more difficult to implement than is worthwhile.

 

Remaining Questions

While the hypertrophy and strength benefits of BFR are clear in healthy older adults, the question remains about the effects of BFR in older adults with more complex comorbidities as we might see in clinic. This reduces the relevancy of many of the studies because of the specific, healthy populations. In particular, patients with higher body fat percentage are an important consideration; is adequate occlusion possible, even with thicker adipose tissue?

Another question remaining is functional training. These studies all utilized knee extension, knee curls, and occasionally leg presses. These tasks isolate and promote strengthening, but are not as functional as a squat or deadlift. It makes sense that BFR-LL with these activities may not directly promote functional improvements. However, if the training itself became functional, would the functional outcomes improve any differently compared to HL training?

Outside of the older adult population, BFR does demonstrate some benefits post surgically. What populations, and what surgeries remain relevant questions for identifying where BFR can provide the most benefit. ACL rehab is the current hot spot in research, but an area of particular interest to me would be post total joint replacement. It is another major surgery involving the knee, with frequent quadriceps deactivation, and increased swelling, and frequently occurs in older adults.

Health Literacy

A key part of this project was breaking down the components of Blood Flow Restriction, particularly because it is still somewhat novel. This meant establishing clear terms, differentiating between different strengthening regimens, and explaining the different metabolic and mechanical stressors that typically drive strengthening. This project relies on students having a good grasp of strength and conditioning, which required more background explanation than initially anticipated. However, we can only recognize BFR’s impact on strength and conditioning if we compare it to more traditional models.

Evaluation

I worked with Jon frequently throughout the semester to review the project, and consider what directions to take it in. We talked about what was relevant about the topic to us as physical therapists, and how to avoid getting stuck in perhaps interesting, but unnecessary red herrings. A big emphasis as we went through was to focus on the safety aspects, and as we reviewed the literature, identifying the neurological impacts of BFR. We discussed how much of this is truly a safety concern, and how it might impact clinical practice. Ultimately, we decided that was important to include in the presentation because physical therapists must have a strong grasp of any and all risk factors to understand patient response, even if it might be mild in the literature.

We also included a feedback form following a presentation to the 1st years, to assess how well the presentation conveyed its message, and to assess any weaknesses in student understanding. First year students appreciated that the topic was focused on recent research, and that it was keeping abreast with current developments in the field. During the live presentation, I really emphasized taking time through the more complex components, including explaining the metabolic ‘why’ of BFR, and numerous students reported that taking the time to cover the foundation of BFR supported their understanding of the topic. Lastly, because of the complexity of the topic, I made sure to design frequent ‘break-down’ or ‘summary slides’ to contextualize new information into the big picture, and to make the slides easier to review should students need to go back.

Separate from the quality of the information itself, was feedback that I spoke a little fast at times during the presentation, which is something I can keep in mind whenever I come into a formal presentation.

Acknowledgments

I would like to thank Jon Hacke for his support and consideration throughout the entire project, as well as Kristin Sommerville and Charles Sheetz for their input.

 

References

1. 1.Hughes, L., Rosenblatt, B., Haddad, F., Gissane, C., McCarthy, D., Clarke, T., . . . Patterson, S. D. (2019). Comparing the effectiveness of blood flow restriction and traditional heavy load resistance training in the Post‑Surgery rehabilitation of anterior cruciate ligament reconstruction patients: A UK national health service randomised controlled trial. Sports Medicine, 49(11), 1787-1805. doi:http://dx.doi.org.libproxy.lib.unc.edu/10.1007/s40279-019-01137-2
2. Rejc E, Floreani M, Taboga P, Botter A, Toniolo L, Cancellara L, Narici M, Šimunič B, Pišot R, Biolo G, Passaro A, Rittweger J, Reggiani C, Lazzer S. Loss of maximal explosive power of lower limbs after 2 weeks of disuse and incomplete recovery after retraining in older adults. J Physiol. 2018 Feb 15;596(4):647-665. doi: 10.1113/JP274772. Epub 2018 Jan 19. PMID: 29266264; PMCID: PMC5813607.
3. Westcott, Wayne L. PhD Resistance Training is Medicine: Effects of Strength Training on Health, Current Sports Medicine Reports: July/August 2012 – Volume 11 – Issue 4 – p 209-216 doi: 10.1249/JSR.0b013e31825dabb8
4. Watson SL, Weeks BK, Weis LJ, Harding AT, Horan SA, Beck BR. High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical Function in Postmenopausal Women With Osteopenia and Osteoporosis: The LIFTMOR Randomized Controlled Trial. J Bone Miner Res. 2018 Feb;33(2):211-220. doi: 10.1002/jbmr.3284. Epub 2017 Oct 4. Erratum in: J Bone Miner Res. 2019 Mar;34(3):572. PMID: 28975661.
5. Cook SB, LaRoche DP, Villa MR, Barile H, Manini TM. Blood flow restricted resistance training in older adults at risk of mobility limitations. Exp Gerontol. 2017 Dec 1;99:138-145. doi: 10.1016/j.exger.2017.10.004. Epub 2017 Oct 5. PMID: 28987643; PMCID: PMC5660944.
6. Vechin FC, Libardi CA, Conceição MS, Damas FR, Lixandrão ME, Berton RP, Tricoli VA, Roschel HA, Cavaglieri CR, Chacon-Mikahil MP, Ugrinowitsch C. Comparisons between low-intensity resistance training with blood flow restriction and high-intensity resistance training on quadriceps muscle mass and strength in elderly. J Strength Cond Res. 2015 Apr;29(4):1071-6. doi: 10.1519/JSC.0000000000000703. PMID: 25264670.
7. Natsume T, Ozaki H, Nakagata T, Machida S, Naito H. Acute Changes in Blood Lactate Concentration, Muscle Thickness, and Strength After Walking with Blood Flow Restriction in Older Adults. Juntendo Medical Journal. 2016;62(Suppl.1):237-242. doi:10.14789/jmj.62.s237
8. Cook SB, LaRoche DP, Villa MR, Barile H, Manini TM. Blood flow restricted resistance training in older adults at risk of mobility limitations. Exp Gerontol. 2017 Dec 1;99:138-145. doi: 10.1016/j.exger.2017.10.004. Epub 2017 Oct 5. PMID: 28987643; PMCID: PMC5660944.