rheumatoid arthritis

Interval Training: A HIIT for RA?

High-intensity interval training (HIIT) tops the American College of Sports Medicine’s list of most popular workouts. According to a small study published in Arthritis Research & Therapy, it might be just the ticket for rheumatoid arthritis (RA), too.

HIIT is an aerobic, heart-pumping form of exercise where short bursts of maximum effort, usually lasting from 20 to 60 seconds, alternate with less intense recovery periods. Studies suggest that HIIT is as effective at burning calories and improving heart and lung health as steady-state exercises like running or biking. One 2018 meta-analysis found that HIIT was significantly better than moderately intense steady exercise for patients with heart disease.

Only a few small studies have looked at HIIT for people who have RA.  On the whole, they showed that participants lost weight, gained muscle and improved their joint health without any increase in inflammation or pain. But researchers at Duke University in Durham, North Carolina, wanted to learn more, including whether HIIT could improve disease activity and immune function.

They enrolled 12 sedentary RA patients, most in their 60s, in a 10-week program of high-intensity interval walking. The participants exercised three times a week for 30 minutes. Each session consisted of a 5-minute warm-up, 20 minutes of HIIT and a 5-minute cool-down.

During the training portion, participants exercised for 60 to 90 seconds at 80 to 90 percent of their maximum effort. High-intensity intervals were followed by active recovery at 50 to 60 percent of their maximum effort. Each participant’s intensity goal was individually determined with a cardiorespiratory fitness test that measures how much oxygen is used during intense exercise.

Because this was a walking-based program, participants never went faster than 4.6 miles per hour. If speed didn’t raise their heart rate enough, researchers increased the incline on the treadmill. Everyone completed all sessions of the program and reported feeling healthier afterward.

HIIT, Health and Immunity

Like other research, the Duke study found that HIIT was as good or better than steady-state exercise for heart and lung health, which improved 9 percent over 10 weeks. Blood pressure, resting heart rate and depression all decreased. And all measures of disease activity, including tender swollen joints, declined by 38 percent.

Other significant changes involved the immune system, especially white blood cells called neutrophils and monocytes. Normally, these are leading actors in the body’s immune response. Neutrophils, for instance, patrol the bloodstream, looking for invading pathogens (disease-producing germs) and are the first responders to infection. But in RA, they overrun inflamed joints, causing even more inflammation, damaging tissue and leaving the body less protected against viruses and bacteria. Monocytes, normally the immune system’s mop-up crew, behave abnormally in RA, too, setting off more inflammation. This immune dysfunction makes people with RA more susceptible to infections – a problem made worse by the use of arthritis drugs that suppress the immune system.

In healthy people, exercise has been shown to improve neutrophil and monocyte function as well as overall immune health. This was also true for the people in the Duke study. After 10 weeks of HIIT, neutrophils were better at homing in on infections and killing pathogens; monocytes returned to a more normal anti-inflammatory state.

The researchers say theirs is the first study to show that a HIIT walking program can improve both disease activity and immune function. It’s also more evidence supporting the well-documented fact that vigorous exercise is exceedingly good for people with arthritis.

But Stephen Messier, PhD, a professor and head of the biomechanics lab at Wake Forest University in North Carolina, points out that the study has limitations, including “a [very] small sample size, no control group and short duration of the intervention period.” Dr. Messier, who was not involved in this study, has spent decades studying the effect of exercise and weight loss on osteoarthritis (OA).

The authors note other problems. The study participants were younger and had less severe disease than many people with RA. It’s not known if HIIT would be as effective for those who are sicker or older. The study also doesn’t take into account people who lack access to a supervised, structured exercise program (such as this one) and a gym.

Still, Dr. Messier says, “The results of this pilot study are encouraging. Most importantly, there were improvements in clinical outcomes that matter to the patient.”

Author: Linda Rath

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