Exercise training augments regional bone and marrow blood flow during exercise.

Area of Science:

• Physiology
• Exercise Science
• Bone Biology

Background:

• Treadmill exercise training increases nitric oxide-mediated vasodilation in the rat femur.
• The impact of exercise training on hindlimb bone and marrow blood flow distribution was previously unknown.

Purpose of the Study:

• To investigate if exercise training improves hindlimb bone and marrow blood flow at rest and during exercise.
• To determine the distribution of blood flow within the femur, tibia, and fibula after training.

Main Methods:

• Six male Sprague-Dawley rats underwent 10-12 weeks of treadmill exercise training (ET).
• Control rats (SED) were acclimated to treadmill exercise.
• Blood flow to nine hindlimb bone regions was measured at rest and during exercise using the microsphere method.

Main Results:

• Exercise training augmented exercise hyperemia in the femoral diaphysis of ET rats compared to SED rats.
• Exercise hyperemia occurred in seven of nine hindlimb bone regions in ET rats, versus only three in SED rats.
• A generalized increase in hindlimb bone and marrow blood flow was observed during physical activity post-training.

Conclusions:

• Exercise training increases hindlimb bone and marrow blood flow during physical activity.
• Elevated blood flow may enhance medullary pressure and interstitial fluid flow.
• These changes suggest a potential benefit to bone integrity from exercise training.