Tolerability of high intensity interval training (HIIT) in individuals living with knee OA and at risk for cardiovascular disease: A prospective cohort study (THIPO)

Objective: To explore the tolerability of a 12-week High Intensity Interval Training (HIIT) program in individuals with knee osteoarthritis (OA) at elevated risk for cardiovascular disease (CVD). Methods: Forty-one individuals with knee OA and elevated CVD risk participated in a 12-week HIIT program with three weekly supervised sessions (36 in total) on treadmills, cross-trainers, row- and cycle ergometers. The program comprised a 10-min warm-up, followed by eight 2-min intervals of high intensity (>80 % of HRmax) followed by 2 min of moderate training intensity (60 % of HRmax), and 5 min of cool down. Tolerability was assessed by investigator consensus using a decision guiding framework based on attendance, incidence of knee pain flares resulting in non-compliance with the HIIT program during the 12-week period and change in knee pain (0–10 scale) at session start from the first to the last week of the program. Results: The average Borg Rating of Perceived Exertion (RPE) score during intervals was 16.2 (SD 1.2) over the 12 weeks. Average attendance to sessions was 88 %. The prevalence of knee flares increased from 3 to 5 from the first to the last 6 weeks, and the number of participants with ≥1 point knee pain reduction from week 1 to week 12 was 19 (46 %). According to KOOS thresholds, participants had mild difficulty in Pain, ADL, and Symptoms; moderate difficulty in Knee-related Quality of Life; and moderate-to-severe difficulty in Function in Sports and Recreation. Conclusion: In conclusion, the HIIT program appeared tolerable for most individuals with knee OA and elevated CVD risk including those with mild-to-moderate difficulties in pain, function, and quality of life, supporting its potential feasibility in this clinical population.