Regular walking improves plasma protein concentrations that promote blood hyperviscosity in women 65-74 yr with type 2 diabetes.

BACKGROUND: The purpose of the present study was to investigate the effects of regular treadmill walking on plasma factors that increase low-shear blood viscosity and red blood cell aggregation in older women with type 2 diabetes. METHODS: Eighteen women with type 2 diabetes (age: 69±3 yr; body mass index: 30.5±5.0 kg⋅m-2) performed 12-wk of 120 min⋅wk-1 of supervised treadmill walking at an intensity equivalent to the gas-exchange threshold. Peak exercise values, anthropometry and blood indices of diabetic status, markers of inflammation, and plasma fibrinogen were analysed during a 6-wk pre-training 'control' period, and then after 6 and 12-wk of regular walking. RESULTS: Regular walking significantly increased peak oxygen uptake (p = 0.01). Body mass, waist to hip ratio, and glycaemic control did not change. Systolic and diastolic blood pressures decreased by 8.5% (p < 0.01) and 7.2% (p < 0.01) respectively, cholesterol to high-density lipoprotein (HDL) ratio decreased by 9.6% (p = 0.01), and HDL concentration significantly increased (p = 0.01). While 12 wk of regular walking did not significantly alter plasma concentrations of interleukin-6 (IL-6), tumour necrosis factor-α, or C-reactive protein, plasma fibrinogen concentration decreased by 6.9% (p < 0.01) and plasma interleukin-10 (IL-10) concentration increased from 1.15±0.32 to 1.62±0.22 mmol⋅L-1 (p < 0.04). CONCLUSIONS: Improved plasma inflammatory profile and decreased plasma fibrinogen concentration is induced by regular walking, independent of glycaemic control. These factors may mediate the improved haemorheology associated with exercise training in metabolic disorders.

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.

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.