The effect of different exercise intensities on health related quality of life in people classified as obese

Aims: To investigate how training intensity influences HRQoL in people classified as obese, if HRQoL changes are related to changes in weight or aerobic capacity, and to define minimal clinically important difference (MCID).

Methodology: Participants (BMI ≥35 kg/m2) randomized into high-intensity training (n = 49), moderate intensity training (n = 39), or no training (n = 22), completed the SF-36 questionnaire, performed a maximal exercise test, and were weighed, before and after a 16-week intervention.

Major findings: High-intensity training showed a significantly greater increase in Physical Summary Scale (PCS), Physical Functioning (PF) and General Health (GH) compared to control, and in Vitality (VT) compared to moderate intensity. Within-group analysis showed that high-intensity training improved PCS 2.0 (0.0–4.4) points (mean (95%CI)), significantly improved mental summary scale (MCS) 3.8 (1.0–6.4) points (mean (95%CI)), PF, GH, VT, mental health, aerobic capacity, and reduced body weight. Moderate intensity training significantly increased PF, GH, aerobic capacity, and reduced weight. No correlations were found between changes in HRQoL and changes in weight or changes in aerobic capacity.

Conclusion: High-intensity training improved HRQoL evaluated with SF-36. HRQoL changes were not correlated with changes in weight or aerobic capacity. Proposed MCIDs are 1.3 points for PCS and 2.0 points for MCS.