Effect of endurance training on muscle microvascular filtration capacity and vascular bed morphometry in the elderly.
OBJECTIVE
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 (K(f)) 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% V(O2peak); P < 0.05; +28% Citrate Synthase Activity; P < 0.01). K(f) 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, K(f) and LC/PF were correlated (r = 0.65, P < 0.05).


CONCLUSIONS
These results demonstrated the microvascular adaptation to endurance training in the elderly. The increase in K(f) 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.
Charles
M
M
Research Unit for Physiology and Physiopathology of Exercise and Handicap, University Jean Monnet, Hôpital Nord, 42055 Saint Etienne Cedex 2, France. marc.charles@univ-st-etienne.fr
Charifi
N
N
Verney
J
J
Pichot
V
V
Feasson
L
L
Costes
F
F
Denis
C
C
D000368:Aged; D000375:Aging / Q000502:physiology*; D001706:Biopsy; D002196:Capillaries / Q000254:growth & development*; D015444:Exercise / Q000502:physiology; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000166:cytology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D010991:Plethysmography; D012039:Regional Blood Flow / Q000502:physiology