These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The nature of the exercise stimulus.
    Author: Rowell LB, Sheriff DD, Wyss CR, Scher AM.
    Journal: Acta Physiol Scand Suppl; 1986; 556():7-14. PubMed ID: 3471059.
    Abstract:
    The two foremost hypotheses concerning the nature of the exercise stimulus are: Central Command. Centrally generated signals activate in parallel cardiovascular and skeletal muscle motor systems; Muscle Chemoreflex. Chemosensitive nerves within the skeletal muscle detect local accumulations of metabolites which reflect disparities between muscle blood flow and metabolism. The focus is mainly on the second hypothesis. The neurophysiological basis for this reflex is well established. Accumulations of metabolites within ischemic muscle reflexly trigger pressor responses that are abolished by blockade of sensory nerves from muscle. However, such blockade does not abolish circulatory responses to static or mild dynamic exercise. To assess the importance of muscle chemoreflexes, stepwise partial occlusions of the terminal aorta were made in exercising dogs. The rise in arterial pressure was related to reductions in terminal aortic flow and arterial pressure below the occluder. In mild exercise sensitivity of the reflex was low until flow was substantially reduced to a threshold. In heavier exercise sensitivity of the reflex was high (no threshold) and could provide a tonically active exercise stimulus. The nature of the metabolic signal is unknown. The pressor response was most closely related to femoral venous lactate concentration and unrelated to femoral venous K+ or PO2.
    [Abstract] [Full Text] [Related] [New Search]