Limb vasodilatory capacity and venous capacitance of trained runners and untrained males

Aerobically trained athletes possess enhanced vasodilatory capacity and venous capacitance in their exercising muscles. However, whether they also possess these characteristics in their non-specific exercising muscles is undetermined. This study examined vasodilatory capacity and venous capacitance of specific (legs) and non-specific exercising muscles (arms) of ten trained runners and ten active but untrained males aged 18–35 years. Venous occlusion plethysmography determined baseline and peak blood flow after 5 min of reactive hyperaemia. Forearm and leg venous capacitance were determined as the difference between baseline and 2 min of venous occlusion at 50 mmHg. During reactive hyperaemia, trained runners had higher leg (48.4±5.3 ml·100 ml tissue⁻¹·min⁻¹) and arm (40.8±2.1 ml·100 ml tissue⁻¹·min⁻¹) vasodilatory capacity compared to the untrained (leg: 37.3±2.5 ml·100 ml tissue⁻¹·min⁻¹; arm: 34.2±2.2 ml·100 ml tissue⁻¹·min⁻¹; P<0.05), and higher calf vascular conductance (0.51±0.06 ml·100 ml tissue⁻¹·min⁻¹·mmHg⁻¹ versus 0.35±0.03 ml·100 ml tissue⁻¹·min⁻¹·mmHg⁻¹; P<0.05). The trained also had higher venous capacitance in both arms (3.5±0.2 ml 100·ml⁻¹) and legs (4.8±0.1 ml·100 ml⁻¹) compared to the untrained (3.0±0.2 ml 100·ml⁻¹; 4.2±0.2 ml·100 ml⁻¹; P<0.05). These findings show that vasculature adaptations to running occur in both specific and non-specific exercising muscles.