Effect of endurance training on muscle microvascular filtration capacity and vascular bed morphometry in the elderly
Exercise training is a strong stimulus for vascular remodelling and could restore age-induced vascular alterations. The purpose of the study was to test the hypothesis that an increase in vascular bed filtration capacity would corroborate microvascular adaptation with training. Methods:
We quantified (1) microvascularization from vastus lateralis muscle biopsy to measure the capillary to fibre interface (LC/PF) and (2) the microvascular filtration capacity (Kf) in lower limbs through a venous congestion plethysmography procedure. Twelve healthy older subjects (74 ± 4 years) were submitted to a 14-week training programme during which lower-limbs were trained for endurance exercise. Results:
The training programme induced a significant increase in the aerobic exercise capacity of lower limbs (+11%Vo2peak; P < 0.05; +28% Citrate Synthase Activity; P < 0.01). Kf was largely increased (4.3 ± 0.9 10−3 mL min−1 mmHg−1 100 mL−1 post-training vs. 2.4 ± 0.8 pre-training, mean ± SD; P < 0.05) and microvascularization developed as shown by the rise in LC/PF (0.29 ± 0.06 post- vs. 0.23 ± 0.06 pre-training; P < 0.05). Furthermore, Kf and LC/PF were correlated (r = 0.65, P < 0.05). Conclusion:
These results demonstrated the microvascular adaptation to endurance training in the elderly. The increase in Kf with endurance training was probably related to a greater surface of exchange with an increased microvessel/fibre interface area. We conclude that measurement of the microvascular filtration rate reflects the change in the muscle exchange area and is influenced by exercise training.