It was once thought among doctors that patients with pulmonary hypertension, many of whom can’t even walk a short distance without being short of breath, shouldn’t exercise. Pulmonary hypertension is a disease that leads to high blood pressure in the arteries of the lungs. When this occurs, the right side of the heart has to work extremely hard and can fail over time, leading to what is termed “exercise intolerance.”
However, recent research has indicated that researchers may have been wrong all along when it comes to recommending exercise to people with pulmonary hypertension. In a study conducted by researchers from the University of Indiana-Purdue entitled “Novel assessment of haemodynamic kinetics with acute exercise in a rat model of pulmonary arterial hypertension” and published in Experimental Physiology, rats with pulmonary hypertension were allowed to exercise in specific ways to see if this worsened or improved pulmonary hypertension. Surprisingly, their condition improved after short periods of significant exercise followed by longer periods of low intensity exercise. The heart function improved as well in the rat subjects.
In response to these findings, Mary Beth Brown, an associate professor and physical therapy researcher in the Department of Physical Therapy at the Indiana University-Purdue, was recently given a substantial NIH grant to fund a new study that will further explore if similar exercise protocols can help humans with pulmonary hypertension.
In the initial studies, rats underwent intense exercise for short periods followed by episodes of less intensive exercise. The rats were hooked up to monitors that could evaluate the heart function and the degree of pulmonary hypertension in the rat subjects. What they found was that this type of exercise improved both pulmonary hypertension and heart function during and after the exercise was completed.
The researchers are still unsure whether repetitive exercise using this protocol will have a long term positive impact on rats (or humans) with pulmonary hypertension. The upcoming research will attempt to mimic the rat exercises in humans to see if there is an optimal exercise protocol that will improve morbidity and mortality in humans with pulmonary hypertension.
Exercise has been thought to negatively impact patients with pulmonary hypertension by causing a lack of efficient energy metabolism in the heart and skeletal muscle of those with the disease. The new research seems to indicate that high intensity exercise for short periods of time followed by rests involving low intensity exercise does just the opposite of what was once thought. In rat models, the thickness of the heart muscle wall actually decreased with this type of exercise protocol, indicating improvement of pulmonary hypertension with exercise.
It is hoped that similarly positive results can be found in humans with pulmonary hypertension so that an optimal exercise program can be instituted to improve morbidity and mortality in those who suffer from this serious disease.