Patients experiencing chronic heart failure (CHF) undergo a variety of issues that can significantly impact their quality of life. One of these issues is their reduced capacity for exercise. One of the factors thought to contribute to this difficulty is the the inspiratory muscle metaboreflex, which regulates blood flow distribution to respiratory and working locomotor muscles during exercise. It is thought that this metaboreflex is impaired in people with chronic heart failure (CHF) and might contribute to their experienced limited exercise capacity.

Research was conducted to determine whether or not inspiratory muscle training (IMT) could help support the metaboreflex and increase quality of life. IMT was tested for improving blood flow to resting and exercising limbs in patients with CHF, improving possible impairments of the inspiratory muscle metaboreflex. Let’s take a closer look at the study below.

Key Findings

• The inspiratory metaboreflex regulates blood flow distribution to the respiratory system and the limbs during respiratory fatigue.
• The inspiratory metaboreflex is impaired in people with heart failure (HF), leading to limited exercise capacity.
• 4 weeks of respiratory muscle training (RMT) improved blood flow to resting calves and exercise forearms during respiratory fatigue.

Patient Impact

RMT effectively improves the blood flow to the limbs during exercise and respiratory fatigue and improves exercise capacity in HF patients.

Study Methods

During the study, blood flow to resting calf and exercising forearm were measured during inspiratory muscle loading via the addition of inspiratory resistance of 60% of maximal inspiratory pressure in patients with CHF. These measurements were made before and after 4 weeks of IMT, and compared to a control group.

Study Results

CHF patients showed a marked decrease in blood flow to resting calf and exercising forearm during inspiratory muscle fatigue when compared to the individuals in the healthy control group. IMT significantly increased blood flow to resting calf and exercising forearm during inspiratory muscle loading in CHF patients, thus improving their exercise capacity.

In conclusion, IMT is an effective method to improve blood flow to resting and exercising limbs under respiratory muscle fatigue, which is markedly reduced in patients with CHF. IMT should therefore contribute to improved exercise tolerance and performance in this patient group.

References

Chiappa GR, et al.Inspiratory Muscle Training Improves Blood Flow to Resting and Exercising Limbs in Patients With Chronic Heart Failure. J Am Coll Cardiol. 2008 Apr 29;51(17):1663-71.