The condition is so named because those who suffer from it have a heart that's too small.
The medical term for the condition is POTS, short for postural orthostatic tachycardia syndrome. About 500,000 in the U.S., mostly young women, are affected.
Among other symptoms, those with POTS have a rapid increase in their heartbeat when they change from lying down to standing. The volume of blood pumped out from the heart with each beat is low. That can make it difficult to stand for long periods. Quality of life can suffer greatly.
''We have come to the conclusion that the essence of the condition is a small, atrophied, deconditioned heart," says study researcher Benjamin D. Levine, MD, director of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital and professor of medicine at the University of Texas Southwestern Medical Center, Dallas.
In the new research, he says, "the heart was too small, we made it bigger [through exercise] and the symptoms went away."
The team found the same benefits to exercise in a previous study. However, in the new study, they found that exercise training made patients feel better without using the beta-blocker medication commonly given to lower the heart rate.
The study results are potentially good news for people like Amy Krakower, 26, a San Diego law school graduate diagnosed at age 23 with the condition. She was so affected, she tells WebMD, that "I couldn't walk up the stairs to my contracts class without feeling like a 90-year-old woman."
The study is published in Hypertension: Journal of the American Heart Association.
Exercise Program for Grinch Syndrome
Levine and his team evaluated 19 people with POTS (including one man) and compared them to 15 people without the condition (including one man).
But Levine's team wanted to find out if reconditioning the patients with the exercise would improve the condition and make the medications unnecessary.
After the medication phase, the researchers found that those on the beta-blockers had no changes in social function scores. Very few had improved physical function scores.
At the beginning of the three-month exercise program, patients worked out on recumbent equipment such as rowers or bikes or they swam. "We started with about three or four times a week, about 25 to 35 minutes including warm-up and cool-down," says study researcher Qi Fu, MD, PHD. She is an assistant professor of medicine at the University of Texas Southwestern Medical Center and a researcher at the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital.
"By the end of three months, they were exercising about five or six hours a week," she says. Besides cardiovascular exercise, they added weight and resistance training. Patients could work out upright as they progressed.
Both the beta-blocker and the exercise training lowered the standing heart rate.
But the patients' quality-of-life scores, including social and physical functioning, were better after the exercise phase but not after the beta-blocker phase.
"Beta-blockers slow the heart rate," Levine says. "Doctors love to see that outcome [so] they prescribe beta-blockers. The problem is, it's not the heart rate that is the issue. And that I think is our message: Just slowing the heart rate doesn't make people feel better."
By the end of the exercise phase, 10 patients no longer met the criteria for the syndrome.
In those with POTS, Levine says, "this isn’t a pathologically small heart, it's a variation of normal."
Grinch Syndrome: One Woman's Story
Krakower calls the study findings exciting. But she is not certain everyone will benefit. She cites disagreement among the medical community about various other problems besides the heart size and condition that can play into having the condition.
There's also the difficulty of being able to exercise, especially if the condition is not well controlled. In the past, she says, "working out was a nightmare." Her heart rate would jump rapidly, at the very beginning of the exercise session.
The inability to stay upright for long periods compromised her life greatly. "It was a very isolating experience," she says. She went from being a very social person to passing up social outings with her law school friends.
These days, her POTS is under more control, she says, thanks to a variety of medications, including a beta-blocker.
"I do work out," she says. "I have been to cardiac rehab, which retaught me the exercises I am allowed to do."
Studying for the bar, as she is doing now, is very time consuming. But she tries to squeeze in workouts. "I know I do feel better when I exercise consistently."
Exercise Not Fit for All
''What [Levine's] study shows is, if you adopt that sort of formal training, you can get good results," says Blair P. Grubb, MD, professor of medicine and pediatrics at the University of Toledo College of Medicine and University Hospital. He cares for many POTS patients.
Grubb tells WebMD he has seen the same results in heart patients. "No one has every questioned whether exercise can work. All of us in the POTS field emphasize reconditioning."
"I believe there is a significant subgroup of individuals who will be able to complete this very rigorous program. But at the same time there will be some patients who won't be able to do this."
Some patients won't be able to do it simply because they don't feel well enough to exercise, he says. Another potential drawback, he says, is the issue of costs, since the exercise program must be overseen by experts.