Lung function and cardiovascular risk: effect of cardiac rehabilitation

Reduced lung function, as measured by the forced expiratory volume in 1 second (FEV1) and the forced vital capacity (FVC), is an independent risk factor for increased cardiovascular morbidity and mortality. Cardiac rehabilitation is known to reduce cardiovascular morbidity and mortality. We therefore investigated whether cardiac rehabilitation would lead to an improvement in lung function.

We measured FEV1 and FVC by using spirometry in 49 participants (age = 65 ± 9 years; 38 men and 11 women) before and after participation in a comprehensive cardiac rehabilitation program.

At baseline, participants were obese with a body mass index (BMI) of 31 ± 6 kg/m, had normal lung function (FEV1 = 89 ± 16% predicted, FVC = 93 ± 14% predicted), and had a peak oxygen uptake (VO2) of 92 ± 21% of predicted. Following cardiac rehabilitation, participants lost weight (ΔBMI = -1.7 ± 4.3%, P = .01) and increased peak VO2 (Δ peak VO2)= 15 ± 17%, P < .0001). There were no statistically significant changes in FEV1 and FVC. However, in the subset of participants with a BMI 30 kg/m or higher (n = 27), there were statistically significant increases in FEV1 (5.1 ± 8.3%, P = .003) and FVC (4.9 ± 9.3%, P = .01), and changes in FEV1 were significantly correlated with changes in BMI (r = -0.58, P = .002).

Lung function improves in association with cardiac rehabilitation only in those participants with a baseline bmi 30 kg/m or higher, and these changes are inversely correlated with loss of weight. this finding suggests that obesity partly explains the association between lung function and cardiovascular risk.