Your trial compared various formats for delivery of exercise therapy to people with stable coronary heart disease. At what stage after a coronary event were participants enrolled in the study?

Participants were required to be at least six months post any coronary event or intervention, such as a heart attack or coronary artery bypass graft surgery, and were required to be clinically stable.

Participants we enrolled ranged from six months to 29 years post the initial event.

What types of exercise training did you compare and were similar doses of exercise compared?

We compared water-based exercise to gym-based exercise and continuing usual activities as a control group.

The exercise programs for both groups were very similar and involved a warm-up and cool-down of light aerobic activity and mobility exercises, with the main training stimulus being a circuit of alternating aerobic and resistance exercises.

The exercise groups were matched for heart rate (progressing from 50 per cent to 80 per cent of the maximum heart rate measured during the baseline exercise test) and the exercises were matched for muscle groups and training time.

The aerobic exercises for the pool sessions involved walking or jogging in the pool and high knee lifts on the spot, whereas in the gym participants walked or jogged on treadmills and used stationary bikes.

The resistance exercises in the pool used custom-made paddles (made from acrylic sheets) on either side of the hand or lower leg and utilised drag resistance.

These exercises involved moving through a set range (for example, knee flexion and extension) and we used waterproof metronomes on headbands to ensure that participants maintained an appropriate speed/resistance.

The participants in the gym used weights machines, free weights and ankle weights for their resistance training.

What issues led you to consider water-based exercise?

We know that exercise is an important component of coronary heart disease (CHD) management and that many people living with CHD don’t meet current exercise guidelines.

We chose to investigate water-based exercise to see if it would be a suitable option for these patients, as it not only helps to increase the variety of options for people to choose from, but also reduces the weight-bearing load through the lower limbs and spine, which may make exercise more comfortable for the high proportion of people with CHD who have musculoskeletal comorbidities.

Had any other trials compared these two types of exercise in this population?

No studies have been done in people with stable CHD comparing water-based exercise and gym-based exercise that assessed peak oxygen uptake and dual-energy X-ray absorptiometry assessments.

Anna Scheer's research compares the effects of water-based training and gym-based training for people with stable coronary heart disease. 

One study has looked at the effect on exercise test time and found positive findings; however, exercise time can be confounded by training type, so using the gold-standard peak oxygen uptake assessment provides more detailed information on this, while dual-energy X-ray absorptiometry provides in-depth information on body composition changes.

How did water-based exercise compare to the gym-based exercise sessions?

Both types of exercise training similarly improved aerobic fitness (peak oxygen uptake), body fat and leg strength.

Gym-based exercise showed improved latissimus pulldown strength over time, suggesting that some additional free weights or different exercises for the upper limbs may be needed for water-based training.

Anecdotally, all participants enjoyed their training sessions.

Would you recommend one form of exercise over the other?

As both types of exercise were similarly effective for most outcomes, client preference would become the deciding factor for recommendations.

The client needs to be willing to commit to the exercise to obtain the health benefits and may prefer a combination of methods.

This research offers clients another exercise option to choose from and may be particularly beneficial for those with CHD and comorbidities such as arthritis or obesity, as there is less weight-bearing load on the lower limb joints and spine.

Where does research in this area need to progress now?

Investigating the effects in the subacute post-event phase would determine if this would be possible as an alternative in cardiac rehabilitation programs.

Other avenues for research to support implementing programs like this in clinical practice could include investigating this type of program in a community setting, either as an ongoing program or as a step-down program to independent exercise, to assess its viability as a long-term strategy for improving exercise participation in people with CHD.

Given that we have now seen positive effects of this program in people with type 2 diabetes and people with CHD, expanding research into this kind of program for other types of chronic disease, or as a preventive measure, is worth consideration.

>> Anna Scheer, APAM, is a physiotherapist who is completing her PhD at Curtin University. Anna is passionate about using water-based exercise to improve health outcomes for people living with chronic disease.