Disturbed hemodynamic cardiac exercise stress test response in non-smoking, normolipidemic, normotensive, diabetic subjects.

OBJECTIVE

The hemodynamic response to exercise is affected by diverse factors such as age, gender and exercise load as well as concomitant pathogenic conditions including smoking, hyperlipidemia, hypertension and possibly diabetes. In this study the hemodynamic response to a graded exercise has been evaluated in diabetic and non-diabetic individuals.

DESIGN AND METHOD: In 3170 consecutive non-smoker normolipidemic normotensive patients, referred for the treadmill exercise test (age 25-70 years), the exercise-induced change in heart rate (DeltaHR) and blood pressure (DeltaSBP and DeltaDBP) was evaluated in 176 diabetics (DM) compared to non-diabetics (NDM).

RESULTS

The results demonstrated that while resting HR and SBP were higher in DM, they had an impaired DeltaHR (62.1+/-20.5 versus 76.4+/-24.2; P<0.0001), DeltaSBP (35.5+/-29.3 versus 42.2+/-24.5; P<0.01) and DeltaDBP (-0.4+/-9.8 versus 2.1+/-15.9; P<0.05) in response to exercise compared to NDM, even among individuals with negative results for exercise test. DM had also lower heart rate reserve, circulatory power and rate-pressure product than NDM (all P<0.0001). While DM were slightly older (57 versus 54.5) and had lower exercise capacity (7.1 versus 8.6 MET) than NDM (both P<0.01), the impact of DM on the hemodynamic changes remained independent and significant after multivariate adjustment for age, exercise load and gender for DeltaHR and DeltaSBP (P<0.01). Exercise-induced DeltaSBP was directly correlated with exercise load and inversely associated with resting pulse pressure (rPP) (P<0.0001). Furthermore, rPP was the second strongest independent predictor for DeltaSBP (beta=-0.22, p<0.0001).

CONCLUSION

The impaired hemodynamic response of DM to exercise and its inverse association with rPP supports the early development of arterial and ventricular stiffness in DM, unrelated to other likely risk factors such as hypertension and hyperlipidemia.