Preliminary findings in the heart rate variability and haemorheology response to varied frequency and duration of walking in women 65–74 yr with type 2 diabetes

Article type: Research Article

Authors: Simmonds, Michael J.^; | Minahan, Clare L.^; | Serre, Kevin R. | Gass, Gregory C. | Marshall-Gradisnik, Sonya M. | Haseler, Luke J.^; | Sabapathy, Surendran^;

Affiliations: Heart Foundation Research Centre, Griffith University, Gold Coast, QLD, Australia | School of Physiotherapy and Exercise Science, Griffith University, Gold Coast, QLD, Australia | Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia

Note: [] Corresponding author: Michael J. Simmonds, School of Physiotherapy and Exercise Science, Gold Coast Campus, Griffith University, QLD 4222, Australia. Tel.: +61 (0) 7 5552 8390; Fax: +61 (0) 7 5552 8674; E-mail: misimmon@bond.edu.au

Abstract: Heart rate variability (HRV) and haemorheology adaptations to 12 wk of varied-dose treadmill walking were investigated in women aged 65–74 yr with type 2 diabetes. Subjects were randomly allocated into two groups where exercise frequency and session duration were manipulated (Group 1 : 2 × 60 min·wk−1 or Group 2 : 4 × 30 min·wk−1), but intensity and accumulated weekly duration of exercise were consistent between groups (100% gas-exchange threshold; 120 min·wk−1). Twelve weeks of exercise training significantly improved peak oxygen uptake, time to exhaustion, and gas-exchange threshold (p < 0.05), independent of exercise group. Exercise training did not significantly change glycaemic control or body mass. Red blood cell (RBC) aggregation and RBC deformability significantly decreased (p < 0.05) for both groups. No change in HRV was observed for Group 1, whereas several key indicators of HRV were significantly improved in Group 2 (p < 0.05). The present study was the first to report decreased RBC aggregation following an exercise-only intervention and that exercise training improved RBC aggregation without a concomitant improvement in glycaemic control. The accumulated weekly exercise duration may be the most important training component for the prescription of exercise in older women with type 2 diabetes.

Keywords: Aggregation, deformability, erythrocyte, exercise, training

DOI: 10.3233/CH-2011-1514

Journal: Clinical Hemorheology and Microcirculation, vol. 51, no. 2, pp. 87-99, 2012