Delayed Heart Rate Recovery and Exaggerated Blood Pressure Response during Exercise Testing in Nigerian Normotensive Diabetics
Ebenezer Adekunle Ajayi *
Department of Medicine, Ekiti State University Teaching Hospital, P.M.B. 5355, Ado Ekiti, Nigeria
Adebayo T. Oyedeji
Department of Medicine, Lautech Teaching Hospital, Osogbo, Nigeria
Akande Oladimeji Ajayi
Department of Medicine, Ekiti State University Teaching Hospital, P.M.B. 5355, Ado Ekiti, Nigeria
*Author to whom correspondence should be addressed.
Abstract
Aim: The aim of this study was to identify the clinical profile of normotensive Type 2 diabetes mellitus (T2DM) with exercise related exaggerated systolic blood pressure (ESBP) and delayed heart rate recovery (HRR); and explore if there is relationship between ESBP and delayed HRR in them.
Materials and Methods: A total of 67 normotensive T2DM subjects underwent symptom limited maximal treadmill exercise using Bruce protocol. ESBP was defined as a peak exercise systolic blood pressure (BP) ≥210 mmHg in men and ≥190 mmHg in women. HRR was defined as the difference in HR from peak exercise to 1 min in recovery; delayed HRR was defined as ≤12 beats/min. Parameters of 36 subjects with ESBP were then compared with those of 31 subjects without ESBP.
Results: There were 36 (53.7%) of the subjects with ESBP. Subjects with ESBP response had higher BMI, 2-hours post-prandial plasma glucose, resting SBP and DBP. Of those with ESBP, 41.7% were males and 58.3% were females (X2=8.75, P=0.003). HRR was lower in subjects with ESBP compared with those without (23.00 ± 12.18 vs 38.55±22.69 beats/minute; P =0.001). The presence of abnormal HRR was 30.6% in subjects with ESBP response compared with 9.7% in subjects without (X2= 4.39, P = 0.036).
Conclusion: ESBP response to exercise is present in more than half of normotensive diabetics and about a third of those patients with ESBP have delayed HRR. Imbalance in the autonomic nervous system, probably heightened sympathetic nervous system, may be responsible for these pathologies.
Keywords: Normotensive diabetes mellitus, exaggerated blood pressure, heart rate recovery