Physician Update: AHA Special Edition
Read more articles from our most relevant research presented at the 2022 AHA Scientific Sessions.
Clinical Heart and Vascular Center
Professor of Internal Medicine
Director, Institute for Exercise and Environmental Medicine
Postural orthostatic tachycardia syndrome, or POTS, is a disorder that primarily affects young women and can be quite disabling. Patients with POTS have a variety of symptoms, but most compelling are light headedness, fatigue, and palpitations in the upright position, accompanied by a rise in heart rate of > 30 bpm when rising from lying down to standing up. Because the disease is “postural,” it is prominently influenced by gravity, which pulls blood below the heart when standing. Indeed, approximately one-fourth to two-thirds of astronauts can’t stand for more than 10 minutes when they return to Earth from space.
My team at UT Southwestern has been studying the mechanisms of “gravity diseases” such as POTS, or patients who faint or can’t stand upright for other reasons, for more than 30 years. Insights derived from experiments done in space, or its ground-based analog, bed rest, have translated into patient-centered therapy for POTS and other challenging diseases like it. In this presentation at #AHA22, I summarized our work with NASA and how it led to our developing a unique exercise program for patients with POTS, a regimen that is now the standard of care for this debilitating condition. Exercise builds their hearts and blood volume, enabling them to stand, exercise, and work normally.
“Insights derived from experiments done in space, or its ground-based analog, bed rest, have translated into patient-centered therapy for POTS and other challenging diseases like it.”
Our work also uncovered a previously unknown link between skeletal muscle and the nerves that sense pain. We found that more than 1,300 genes in muscle are up or down regulated during bedrest, and many of these genes alter the activity of specific pain-sensing nerves. Further, muscle from volunteers who exercised in bed had a tenfold reduction in the genes that were altered by bedrest, thereby reducing this enhanced pain sensitivity. In the future, we will partner with Steve Vernino, M.D., Ph.D., in the UT Southwestern Department of Neurology to determine how to better classify these diverse patients as we work toward developing even more effective therapies for them.