# Exercise as it relates to Disease/Taking Cardiac Rehabilitation Home: Home-Based Interval Training for Heart Failure Patients

This Wikipage is an analysis of a study by Safiyari-Hafizi, H et al. on "The Health Benefits of a 12-Week Home-Based Interval Training Cardiac Rehabilitation Program in Patients With Heart Failure", published in the Canadian Journal of Cardiology (2016).

## What is the background to this research?

Heart Failure (HF) is a significant public health issue effecting over 23 million people worldwide and rising. HF is a major risk factor for morbidity and mortality, contributing substantially to health care costs as it is associated with frequent hospital admission and readmissions.
Advancements in the treatment and prevention of cardiovascular disease, including acute HF along with an aging population predict a continual increase in the prevalence of HF and thus an increased burden of care on health systems. For these reasons research into optimal rehabilitation methods is highly warranted. Traditional cardiac rehabilitation programs are hospital-based and include moderate-intensity, continuous exercise. Recently there has been a growing attention into high-intensity rehabilitation training in HF patients. Less is known about home-based rehabilitation and the optimal program has not been established. Home-based training is potentially more convenient for patients and may have greater rates of compliance. Home-based training may also help to reduce the burden of care placed on hospital systems however some safety and efficacy concerns surround this area.

## Where is the research from?

This study was published in the Canadian Journal of Cardiology and was conducted in Canada among adults with stable HF. Funding for this study was provided by a BC Sports Medicine Research Foundation Grant as well as other health research bodies including the Canadian Institutes of Health Research, the Michael Smith Foundation for Health Research, the Canada Foundation of Innovation, the Natural Sciences and Engineering Research Council of Canada, and GE Healthcare. The authors claim there was no conflict of interest to disclose.

## What kind of research was this?

This study was a randomised control trial (RCT) which compared an experimental group (home-based rehabilitation of high-intensity interval training and resistance training) to a control group.
The authors claim that to their knowledge, no previous studies have examined the efficacy of a high-intensity HF rehabilitation program in a home-based setting and therefore no direct comparison can be made with other studies. Several studies, including other RCT's have explored the effect of high-intensity and interval training in a medically supervised setting and there is growing evidence to suggest improved health benefits with interval training in cardiac rehabilitation including patients with HF. The effects of home-based interval training have been studied to a lesser extent in patients with HF although home-based interval training has been suggestive of long term health benefits and exercise adherence in patients with coronary artery disease. A recent meta-analysis showed that interval training had greater effects in improving peak aerobic power compared to traditional continuous aerobic training in HF patients.

## What did the research involve?

Participants in the experimental group followed an individualised 12 week home-based interval walking program and resistance exercises. Participants used heart rate monitors, pedometers and log books to record their training. Programs were individualised based on the patient's current condition, peak aerobic power, medications and activity levels. The walking program included interval training using heart rate zones, with high-intensity phases of 80-85% VO$_2$peak and periods of active recovery at 40-50%VO$_2$peak. The duration of intensity intervals varied according to the functional capacity of the individual. Resistance training was also included using resistance bands and participants were provided instructions to follow. Participants in the exercise group were supervised by a clinical exercise specialist via telephone, Internet and fax on a weekly basis.
Participants in the control group did not receive any formal exercise program or supervision. They were instructed to continue with their normal daily activities and as per usual clinical practice they were encouraged to continue with moderate exercise at the intake clinic.
Measurements used:
* Exercise capacity: was estimated using the 6-minute walk test.
* Cardiopulmonary stress testing: via an incremental exercise test using a cycle ergometer was used to assess VO$_2$peak, power output, blood pressure and oxygen saturation.
* Quality of life: was assessed using the Minnesota Living with Heart Failure Questionnaire.
Specific activity undergone by the control group was not documented, which can be considered a limitation of this study. Further limitations in this study exist around the small sample size (29 participants completed the study) as well as the sample population tested was restricted to people below 75 years of age and represented largely male participants.

## What were the basic results?

The results of this study found improvements in some aspects of the experimental group (combination of high-intensity interval training and resistance training in a home-based setting) compared to the control group. The findings have been summarised in the table below.
| Significant improvements in experimental vs control group | No significant improvements in between groups |
| VO$_2$peak Exercise capacity Quality of life Oxygen consumption at ventilator threshold | Peak power output Oxygen pulse Minute ventilation |

## What conclusions can we take from this research?

From this research study it can be concluded that:
* A combination of high-intensity interval training and resistance training in a home-based setting is an effective rehabilitation strategy for patients with HF over a 12 week period.
* Patient supervision can be provided using consistent (weekly) follow-ups.
* An individualised, home training program is an effective intervention for exercise adherence and reducing the risk of adverse exercise-related events.

## Practical advice

The findings of this study can be applied practically in the treatment of HF and are particularly relevant in an outpatient setting, when patients live remotely or do not have access to a hospital based rehabilitation. Patient supervision was provided via consistent follow-ups which appeared to be an effective means in addressing patient safety.
The exercise intensity and work to rest ratios were individually determined for each patient in the study. This individualised approach may lead to improved patient adherence and reduced risk of exercise-related adverse events. However when considering practical implications this option may be more time consuming and costly compared to a generic training approach. Further investigation is warranted to compare an individualised versus generic training intensity in a home-based setting.
Investigation to determine the effect of home-based rehabilitation on health care costs as well as the implications on morbidity and mortality in HF patients should also be considered.

## Further information/resources

* Learn more about Chronic Heart Failure: https://heartfoundation.org.au/your-heart/heart-conditions/chronic-heart-failure-the-facts
* Visit the Heart Foundation website for further information and contact details for cardiac rehabilitation services: https://heartfoundation.org.au/your-heart/living-with-heart-disease/cardiac-rehabilitation
* HEART Online shows clinician resources for cardiac rehabilitation and heart failure management: http://www.heartonline.org.au/
* Learn about the Australian guidelines for the prevention, detection and management of chronic heart failure: https://heartfoundation.org.au/images/uploads/publications/Chronic_Heart_Failure_Guidelines_2011.pdf
* The Heart Foundation has created a free mobile app to help manage medications and health stats which can be downloaded at this link: https://myheartmylife.org.au/

## References

* 1 2 3 4 5 6 7 8 9 10 11 12 13 Safiyari-Hafizi, H., Taunton, J., Ignaszewski, A., & Warburton, D. E. R. (2016). The Health Benefits of a 12-Week Home-Based Interval Training Cardiac Rehabilitation Program in Patients With Heart Failure. Canadian Journal of Cardiology, 32(4), 561-567. doi: 10.1016/j.cjca.2016.01.031
* 1 2 Bui, A. L., Horwich, T. B., & Fonarow, G. C. (2011). Epidemiology and risk profile of heart failure. Nature Reviews Cardiology, 8(1), 30-41. doi: 10.1038/nrcardio.2010.165
* ↑ 6. WisloffU, Stoylen A, Loennechen JP, et al. Superior cardiovascular effect of aerobic interval training versus moderate continuous training in heart failure patients: a randomized study. Circulation 2007;115:3086-94.
* ↑ Aamot, I. L., Karlsen, T., Dalen, H., & Stoylen, A. (2016). Long-term Exercise Adherence After High-intensity Interval Training in Cardiac Rehabilitation: A Randomized Study. Physiotherapy Research International, 21(1), 54-64. doi: 10.1002/pri.1619
* ↑ Haykowsky, M. J., Timmons, M. P., Kruger, C., McNeely, M., Taylor, D. A., & Clark, A. M. (2013). Meta-Analysis of Aerobic Interval Training on Exercise Capacity and Systolic Function in Patients With Heart Failure and Reduced Ejection Fractions. American Journal of Cardiology, 111(10), 1466-1469. doi: 10.1016/j.amjcard.2013.01.303