# Exercise as it relates to Disease/The effect of resistance training on cardiovascular function in patients with Peripheral Artery Disease

A critical appraisal of the research article 'Effects of Resistance Training on Cardiovascular Function in Patients With Peripheral Artery Disease: A Randomized Controlled Trial' by Gomes et al., 2018 and published in The Journal of Strength and Conditioning Research.

## What is the background to this research?

Peripheral artery disease (PAD) is characterised as decreased arterial perfusion mainly affecting the body's lower extremities. The disease affects over 200 million people worldwide and is most prevalent in older adults, with its occurrence being 20% of people aged 70 years and above. Patients with PAD may suffer from pain in the thighs and calves which can negate their walking capacity, therefore resistance training (RT) may be an effective intervention to both improve a patient's gait as well as quality of life outcomes. Patients with PAD have increased risk of stroke, myocardial infarction and many other cardiovascular related diseases and morbidity. Therefore the main aim of this artcle was to investigate whether RT can reduce cardiovascular risk factors, particularly resting and ambulatory (24-hour) blood pressure.
Previous research on the effect of RT on blood pressure in patients with PAD has been conflicting. One study found a decrease in resting blood pressure following a 24-week intervention, whilst others have found no significant difference. This article being appraised builds on previous knowledge by assessing both resting BP and ambulatory BP, whereas all previous studies have only looked at clinical BP. Ambulatory BP measurements have been shown to be a more compelling predictor of all-cause and cardiovascular mortality than clinical measurements. Furthermore, The variation in BP that is obtained from ambulatory measurements is an independent risk factor of cardiovascular related events and death.

## Where is the research from?

The article being appraised is published in the Journal of Strength and Conditioning Research (JSCR). This journal is monthly peer-reviewed and releases articles of all kinds related to physical activity, performance, health and diseased populations.
All authors on the article are associated with various University's across Brazil. The lead author, Ana Gomes, is a part of the Associated Graduate Program in Physical Education UPE/UFPB at the University of Pernambuco in Recife-PE, Brazil. This author has a particular interest in peripheral artery disease, although is only involved in one other publication in 2015, potentially impacting the credibility of the current article due to lack of experience.
The study was supported through grants from Brazilian Federal Government organisations including The Brazilian National Council for Scientific and Technological Development. It has been declared there are no conflicts of interest and the results of the study would not financially endorse the authors in any way.

## What kind of research was this?

The article being appraised was conducted as a randomised controlled trial. This involved the subjects being assigned randomly using randomizer.org to either an experiment group or a control group. randomised controlled trials are the most precise way of investigating a cause-effect relationship between the treatment and the outcome.
These are more effective than non-randomised trials as they produce the least possible bias and can be assured that the outcome did not come from any factors outside the treatment intervention.

## What did the research involve?

Participants with peripheral artery disease between the ages of 40 and 80 were recruited to participate. The study went for 12 weeks and clinical and ambulatory cardiovascular measurements were taken before and after. A strength of the procedure was taking BP measurements at the same of day, which was done to avoid the influence of circadian variation. Participants were also told to withhold from alcohol, caffiene and smoking at least 24 hours before measurements were taken, although there was no indication of testing for this and therfore BP may have been affected if the subjects didn't comply.
Participants were randomly assigned to one of two groups:
Resistance training group:
* Approximately 40 minute sessions
* 2 sessions per week
* 3 sets of 10 repetitions per exercise with 2 minute rest intervals
* All exercises were performed at moderate intensity of 5-7/10 rate of perceived exertion on the OMNI scale
Control group:
* Approximately 40 minute sessions
* Whole body stretching and relaxation exercises
* Used to equalise attention with the experiment group and retain subjects throughout
Exercises in each group :
| Resistance training group | Control group |
| Exercises: Bench press Leg press Seated row Knee extension Arm curl Leg curl Frontal raise Hip abduction | Exercises: Whole body stretching Whole body relaxation |
table 1: exercises performed in RT and control groups
9 out of the original 30 participants dropped out of the study, leaving only 11 subjects in the RT group and 10 subjects in the control group completing the study. This sample size was far too small which may be a contributing factor to the limited results.

## What were the basic results?

Main findings:
* Resistance training resulted in a decrease in diastolic BP variability across 24 hours (table 2)
* No significant change in resting BP and cardiovascular parameters between groups
* No significant change in 24-hour BP between groups
Diastolic BP variability (mm Hg) of RT group :
| | Change from pre-post intervention |
| 24 hour | -0.8 ± 0.32 |
| Awake | -1.1 ± 0.58 |
| Asleep | 0.8 ± 1.00 |
table 2: Diastolic BP variability in the RT group
Blood pressure variability was the only parameter be reduced by resistance training. Resting and 24-hour blood pressure levels showed no statistical difference between groups.

## What conclusions can we take from this research?

It is evident through this appraised article that a resistance training intervention can have a positive effect on cardiovascular parameters through the reduction in blood pressure variability across 24 hours. As previously mentioned, patients with PAD have an increased risk of stroke, myocardial infarction and other cardiovascular complications, and therefore making it important to reduce risk factors such as high blood pressure levels and variability.
In a similar article, it was found that after a 12-week resistance training intervention, resting blood pressure was reduced in patients with intermittent claudication. However, subjects in this trial were exercising at 11-13 on 15 grade Borg scale. As participants were only training at moderate intensity (5-7 OMNI scale) in the appraised article, it may not have been intense enough to elicit resting blood pressure adaptations.
Further research should also look into the utilisation of other forms of exercise such as aerobic training to supplement resistance training.

## Practical advice

* The findings of RT being linked to decreased blood pressure variability propose that it can be used as an effective treatment option in reducing risk factors for cardiovascular related complications.
* Regular physical activity of any kind is extremely important as is has been associated with lower blood pressure, reduced risk of stroke and other cardiovascular complications.
* People suffering from PAD should always seek professional guidance when exercising to ensure safety, especially when it comes to resistance training and the potential risks associated with it.

## Further information/resources

Peripheral artery disease information
* Centers for Disease Control and Prevention
* Heart Foundation
Further research
* Combined Aerobic and Resistance Exercise in Walking Performance of Patients With Intermittent Claudication: Systematic Review
* Exercise Training and Peripheral Arterial Disease

## References

* 1 2 3 4 5 6 7 Gomes, Ana P.F.; Correia, Marilia A.; Soares, Antônio H.G.; Cucato, Gabriel G.; Lima, Aluísio H.R.A.; Cavalcante, Bruno R.; Sobral-Filho, Dário C.; Ritti-Dias, Raphael M. Effects of Resistance Training on Cardiovascular Function in Patients With Peripheral Artery Disease: A Randomized Controlled Trial. Journal of Strength and Conditioning Research: April 2018 - Volume 32 - Issue 4 - p 1072-1080 doi: 10.1519/JSC.0000000000001914
* 1 2 Zemaitis MR, Boll JM, Dreyer MA. Peripheral Arterial Disease. [Updated 2022 Jul 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430745/
* ↑ Hirsch AT, Duval S. The global pandemic of peripheral artery disease. Lancet. 2013 Oct 19;382(9901):1312-4. doi: 10.1016/S0140-6736(13)61576-7. Epub 2013 Aug 1. PMID: 23915884.
* ↑ Ritti-Dias RM, Wolosker N, de Moraes Forjaz CL, Carvalho CR, Cucato GG, Leao PP, de Fatima Nunes Marucci M. Strength training increases walking tolerance in intermittent claudication patients: Randomized trial. J Vasc Surg 51: 89–95, 2010.
* 1 2 Alberts MJ, Bhatt DL, Mas JL, Ohman EM, Hirsch AT, Röther J, Salette G, Goto S, Smith SC Jr, Liau CS, Wilson PW, Steg PG; REduction of Atherothrombosis for Continued Health Registry Investigators. Three-year follow-up and event rates in the international REduction of Atherothrombosis for Continued Health Registry. Eur Heart J. 2009 Oct;30(19):2318-26. doi: 10.1093/eurheartj/ehp355. Epub 2009 Aug 31. PMID: 19720633; PMCID: PMC2755116.
* ↑ McGuigan MR, Bronks R, Newton RU, Sharman MJ, Graham JC, Cody DV, Kraemer WJ. Resistance training in patients with peripheral arterial disease: effects on myosin isoforms, fiber type distribution, and capillary supply to skeletal muscle. J Gerontol A Biol Sci Med Sci. 2001 Jul;56(7):B302-10. doi: 10.1093/gerona/56.7.b302. PMID: 11445595.
* ↑ Banegas, J., Ruilope, L., de la Sierra, A., Vinyoles, E., Gorostidi, M., de la Cruz, J., Ruiz-Hurtado, G., Segura, J., Rodríguez-Artalejo, F. and Williams, B., 2018. Relationship between Clinic and Ambulatory Blood-Pressure Measurements and Mortality. New England Journal of Medicine, 378(16), pp.1509-1520.
* 1 2 https://journals.lww.com/nsca-jscr/pages/default.aspx
* ↑ Correia MA, Soares AH, Cucato GG, Lima AH, Gomes AP, Prazeres TM, Rodrigues SC, Sobral-Filho D, Santos AC, Brasileiro-Santos MS, Ritti-Dias RM. Vascular Mechanisms of Post-exercise Blood Pressure Responses in Peripheral Artery Disease. Int J Sports Med. 2015 Nov;36(13):1046-51. doi: 10.1055/s-0035-1555853. Epub 2015 Aug 7. PMID: 26252549.
* 1 2 Sibbald B, Roland M. Understanding controlled trials: Why are randomised controlled trials important? BMJ 1998; 316 :201 doi:10.1136/bmj.316.7126.201
* ↑ Robertson, Robert & Goss, Fredric & Rutkowski, Jason & Lenz, Brooke & Dixon, Curt & Timmer, Jeffrey & Frazee, Krisi & Dubé, John & Andreacci, Joseph. (2003). Concurrent Validation of the OMNI Perceived Exertion Scale for Resistance Exercise. Medicine and science in sports and exercise. 35. 333-41. 10.1249/01.MSS.0000048831.15016.2A.
* ↑ Grizzo Cucato G, de Moraes Forjaz CL, Kanegusuku H, da Rocha Chehuen M, Riani Costa LA, Wolosker N, Kalil Filho R, de Fátima Nunes Marucci M, Mendes Ritti-Dias R. Effects of walking and strength training on resting and exercise cardiovascular responses in patients with intermittent claudication. Vasa. 2011 Sep;40(5):390-7. doi: 10.1024/0301-1526/a000136. PMID: 21948782.
* ↑ Hegde SM, Solomon SD. Influence of Physical Activity on Hypertension and Cardiac Structure and Function. Curr Hypertens Rep. 2015 Oct;17(10):77. doi: 10.1007/s11906-015-0588-3. PMID: 26277725; PMCID: PMC4624627.