Poorer positive affect in response to self-paced exercise among the obese

We aimed to investigate the association between body mass index (BMI) and affective response, ratings of perceived exertion (RPE), and physiological responses during self-paced exercise. Sixty-six women were divided into three groups accordingly with the BMI: obese (n = 22: 33.5 ± 8.5 yr; 34.9 ± 4.1 kg∙m^-2), overweight (n = 22: 34.8 ± 8.6 yr; 26.4 ± 1.3 kg∙m^-2), and normal-weight (n = 22: 30.8 ± 9.3 yr; 22.0 ± 1.6 kg∙m^-2). They underwent a graded exercise test and a 20-min self-paced walking session on a treadmill. Affective responses, RPE, heart rate (HR), and oxygen uptake (VO₂) were recorded every 5 min. The women with obesity experienced the lowest affective rates (p < .001), despite similar RPE, HR, and VO₂ to the other normal weight and overweight groups. In addition, a multiple regression model indicated that BMI was a significant predictor of affective responses (p < .001). In conclusion, the results of the present study suggest that obesity is associated with poorer affective responses to exercise even at self-paced intensity, with the same physiological responses and perceived exertion. Therefore, techniques that aim directly to increase pleasure and/or reduce attentional focus and perception of effort in this population are required, such as affect-regulated prescription, shorter bouts of self-paced exercise throughout the day, distraction away from internal cues (e.g. music, group exercise), etc.