A recent study by researchers at Karolinska Institutet has found that high-intensity interval training (HIIT) is more effective than traditional home exercise programs in improving fitness and muscle endurance for people recently diagnosed with inflammatory muscle disease. The findings were published in eBioMedicine.
Idiopathic inflammatory myopathies (IIM) are rare autoimmune conditions characterized by muscle weakness and fatigue. Standard treatment typically combines medication with light to moderate home-based exercise, but this approach has shown limited improvement in aerobic fitness.
The research team studied 23 patients who had recently developed IIM. Participants were recruited from Karolinska University Hospital in Stockholm and Uppsala University Hospital in Sweden. They were randomly assigned to two groups: one performed HIIT on a stationary bike three times per week for twelve weeks, while the other followed a moderate-intensity home exercise program.
Aerobic capacity, muscle endurance, and markers of disease activity were measured before and after the training period. According to the results, "the HIIT group improved their aerobic capacity by an average of 16 percent, compared with 1.8 percent in the home exercise group." Muscle endurance gains were also higher among those performing HIIT. Muscle samples indicated better mitochondrial function, which is important for energy production within cells.
Disease activity remained stable across both groups during the study period, suggesting that intensive training did not increase inflammation or cause additional muscle damage.
Researchers noted that the study size was small and called for further research to confirm these findings and evaluate long-term effects. The study received funding from several organizations including the Swedish Research Council, Region Stockholm (ALF), the Swedish Rheumatism Association, King Gustaf V's 80-Year Fund, and the Swedish Heart Lung Foundation.
