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.