Influence of physical inactivity on arterial compliance during a glucose challenge

Abstract

Acute hyperglycemia has been shown to augment indices of arterial stiffness in patients with insulin resistance and other co-morbidities, however, conflicting results exist in healthy young individuals. We examined if acute hyperglycemia following an oral glucose tolerance test (OGTT) increases arterial stiffness in healthy active men before, and then after reduced ambulatory physical activity to decrease insulin sensitivity. High-resolution arterial diameter tracings acquired from Doppler-ultrasound allowed the obtainment of an arterial blood pressure (BP) waveform from the diameter tracing within a cardiac cycle. In 24 subjects, this method demonstrated sufficient agreement with the traditional approach for assessing arterial compliance using applanation tonometry. In 10 men, continuous recordings of femoral and brachial artery diameter, and beat-to-beat BP (Finometer) were acquired at rest, 60, and 120 mins of an OGTT before and after 5 days of reduced activity (> 10,000 to < 5,000 steps/day). Compliance and beta-stiffness were quantified. Prior to reduced activity, OGTT had no effect on arterial compliance or beta-stiffness. However, following reduced activity, femoral compliance was decreased (rest = 0.10 ± 0.03 to 120-min OGTT = 0.06 ± 0.02 mm² mmHg⁻¹; P < 0.001) and femoral beta-stiffness increased (rest = 8.7 ± 2.7 to 120-min OGTT = 15.3 ± 6.5 AU; P < 0.001) during OGTT, while no changes occurred in brachial artery compliance (P = 0.182) or stiffness (P = 0.892). Insulin sensitivity (Matsuda Index) was decreased following reduced activity (P = 0.002). In summary, in young healthy men, the femoral artery becomes susceptible to acute hyperglycemia following 5 days of reduced activity and the resultant decrease in insulin sensitivity, highlighting the strong influence of daily physical activity levels on vascular physiology.

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