Japanese Heart Journal
Online ISSN : 1348-673X
Print ISSN : 0021-4868
ISSN-L : 0021-4868
Clinical Studies
Serum HbA1c Levels and Exercise Capacity in Diabetic Patients
Ibrahim DemirCengiz ErmisHasan AltunbasM. Kemal Balci
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2001 Volume 42 Issue 5 Pages 607-616


It is well known that cardiovascular morbidity and mortality are high in diabetic patients. Cardiac involvement is silent and early and these diabetic patients generally complain of chronic fatigue. This study was designed to evaluate the relation between glycemic control and exercise capacity in 330 diabetic patients who have no cardiac symptoms by sustaining dynamic exercise. After a cardiac examination, patients with coronary heart disease, ECG abnormalities, cardiac failure, valvular disease, cerebrovascular disease, peripheral artery disease, anaemia and peripheral neuropathy were excluded. Plasma HbA1c and lipid levels were obtained and a symptom limited exercise test based on “Bruce Protocol” was performed on all patients. Plasma HbA1c levels were significantly increased in smokers and in hypercholesterolemic patients (p<0.001, p=0.006). A moderate correlation between exercise capacity and HbA1c levels, and a weak correlation between duration of diabetes, age, sex, hypertension and plasma lipids were obtained. Multivariant regression analys is revealed that only HbA1c and hypercholesterolemia affected exercise capacity independently (r=-0.54 r=-0.30). In conclusion, poor glycemic control in diabetic patients causes earlier cellular involvement. Because of the high affinity of HbA1c to oxygen, the energy metabolism of the cell is affected, with a clinical correlation betreen chronic fatigue and worsening exercise capacity.

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© 2001 by the Japanese Heart Journal
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