Aerobic exercise training without weight loss reduces dyspnea on exertion in obese women

Abstract

Dyspnea on exertion (DOE) is a common symptom in obesity. We investigated whether aerobic exercise training without weight loss could reduce DOE. Twenty-two otherwise healthy obese women participated in a 12-week supervised aerobic exercise training program, exercising 30 min/day at 70-80% heart rate reserve, 4 days/week. Subjects were grouped based on their Ratings of Perceived Breathlessness (RPB) during constant load 60 W cycling: +DOE (n=12, RPB≥4, 37±7 years, 34±4 kg/m(2)) and -DOE (n=10, RPB≤2, 32±6 years, 33±3 kg/m(2)). No significant differences between the groups in body composition, pulmonary function, or cardiorespiratory fitness were observed pre-training. Post-training,peak was improved significantly in both groups (+DOE: 12±7, -DOE: 14±8%). RPB was significantly decreased in the +DOE (4.7±1.0-2.5±1.0) and remained low in the -DOE group (1.2±0.6-1.3±1.0) (interaction p<0.001). The reduction in RPB was not significantly correlated with the improvement in cardiorespiratory fitness. Aerobic exercise training improved cardiorespiratory fitness and DOE and thus appears to be an effective treatment for DOE in obese women.

Keywords: Breathlessness; Cardiorespiratory fitness; Exercise; Obesity; Shortness of breath.

Fig. 1

$\stackrel{\cdot }{V}{\mathrm{O}}_2$ peak (as% of predicted weight) increased significantly in all subjects following aerobic exercise training. Values are mean ± SD. *p < 0.0001.

Fig. 2

RPB decreased significantly following aerobic exercise training in the +DOE group, but remained low in the −DOE group. Values are mean ± SD. *p < 0.001 group* exercise training interaction.

Fig. 3

The change in breathlessness ratings (Δ RPB) was not significantly correlated with the change in oxygen uptake. Δ $\stackrel{\cdot }{V}{\mathrm{O}}_2$ is the change in oxygen uptake at 60W following aerobic exercise training.