Exercise can feel more difficult and draining than usual if you have rheumatoid arthritis, and it’s not just because of the stiff and painful joints caused by this autoimmune disorder. In a groundbreaking new experiment involving older women and exercise, researchers found that even a gentle session of leg lifts set off an exaggerated nervous system reaction in those with rheumatoid arthritis. Light exercise also negatively affected the inner workings of their muscles and blood vessels.
The findings build on earlier research about rheumatoid arthritis and the nervous system and raise pressing new questions about the best and safest ways for people with this disorder or similar autoimmune diseases to become and remain active.
Anyone who has rheumatoid arthritis or is close to someone who has it knows the havoc it creates in the body. Immune cells mistakenly attack healthy tissue, especially in joints, causing swelling, pain and deterioration, along with full-body inflammation and fatigue. Rheumatoid arthritis also often results in cardiovascular disease, which initially puzzled doctors, since the misguided immune cells do not directly target the heart or arteries.
But in recent years, researchers discovered that people with rheumatoid arthritis tend to have unusually twitchy sympathetic nervous systems. The sympathetic nervous system is the portion of our internal wiring that stimulates the fight-or-flight response, biochemically alerting our brains, heart, muscles and other bodily systems to brace ourselves for impending danger. The opposing parasympathetic nervous system, the Matthew McConaughey of our internal biology, lulls us, sending signals that quiet the sympathetic upsets.
But in rheumatoid arthritis patients, researchers found, the sympathetic system seems stuck in overdrive, keeping people’s internal operations constantly on edge. A result is a high risk for elevated blood pressure and heart rate, even when people are resting quietly, which contributes over time to cardiovascular disease.
Few of those earlier studies, though, looked at exercise, which also raises blood pressure and heart rates and changes nervous system reactions. Some past studies — and considerable anecdotal evidence — had indicated that people with rheumatoid arthritis feel more fatigue during and after activity than other exercisers. Their heart rates and blood pressures also remain stubbornly elevated for longer after workouts. But what might be going on inside their nerves and muscles leading to these reactions has been mostly unclear.
So, for the new study, which was published in February in The Journal of Physiology, scientists at the University of São Paulo in Brazil decided to ask people with rheumatoid arthritis to do a little resistance training. Turning to patients at the university’s rheumatology clinic, they recruited 33 older women with rheumatoid arthritis and another 10 older women without the condition, to serve as controls. Most of them, in both groups, were on various medications.
They invited all of their volunteers to the lab, drew blood, asked about their current pain levels, tested blood pressure and other health markers, and gently embedded tiny sensors beneath the skin in one leg to measure nervous system activity. Finally, they asked each woman to complete leg lifts with that leg, using a standard weight machine set to a low resistance. The women were supposed to lift repeatedly for three minutes — although some quit earlier than that — while the researchers tracked their blood pressures, nervous system reactions, and markers of muscular response, during and immediately afterward.
What they found when they compared results was that “the women with R.A. showed greater blood pressure and sympathetic responses” to the light workout than those in the control group, says Tiago Peçanha, a postdoctoral research associate at the University of São Paulo who was a co-author of the new study with his doctoral adviser Hamilton Roschel, the director of the university’s Laboratory of Assessment and Conditioning in Rheumatology, and others.
Their nerves seemed especially sensitive to the buildup of certain substances in the working muscles, the researchers concluded, which prompted the nerves to send urgent messages to nearby blood vessels, ordering them to contract. The result was lingering high blood pressure, during and after the workout.
These reactions were most marked among the rheumatoid arthritis patients with the highest levels of inflammatory activity in their blood before the exercise, the researchers found.
Taken as a whole, the findings indicate that physical activity can be extra difficult for people with rheumatoid arthritis, because their nervous systems may overreact to relatively minor changes inside the muscles.
But the findings do not suggest that those with the autoimmune disorder should avoid exercise, Dr. Roschel says. “Physical activity is highly recommended for people with R.A,” he points out. “But these individuals may require additional attention and support to engage in physical activity programs.”
If you have been diagnosed with rheumatoid arthritis, talk with your physician or an exercise physiologist about how best to exercise, he says. And if you begin a new routine, start slowly and perhaps keep a log of how you feel during workouts.
Of course, this study focused on older women with rheumatoid arthritis and a single session of very light resistance training. It is unknown whether the results apply equally to younger women or men with the condition, or whether other types of exercise, such as walking, may produce a similar response. It is also unknown how those with different autoimmune diseases or related conditions might be affected.
Dr. Roschel and his colleagues are looking into all of those questions, though. “We have also been conducting some exercise studies with patients who have recovered from Covid-19 in our lab, and they also present abnormal cardiorespiratory responses to exercise,” he says. They hope to publish additional studies soon.