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: Noninvasive determination of exercise-induced vasodilation during bicycle exercise using near infrared spectroscopy.
    Author: Kime R, Im J, Moser D, Nioka S, Katsumura T, Chance B.
    Journal: Med Sci Monit; 2009 Mar; 15(3):CR89-94. PubMed ID: 19247245.
    Abstract:
    BACKGROUND: The purpose of this study was to examine the changes in total hemoglobin (Delta[tHb]) response during bicycle exercise at various constant workloads using near infrared continuous wave spectroscopy (NIRcws) in humans. We hypothesized that the Delta[tHb] during exercise may progressively increase as a result of a dilation of the vascular bed and/or capillary recruitment at lower constant work rates. MATERIAL/METHODS: Seven healthy subjects performed bicycle exercise at 20, 40, 60, 80, and 100% of maximal work rates (Wmax) for 5 min. Muscle oxygenation change (Delta[Oxy]) and Delta[tHb] at the right vastus lateralis were monitored using a NIRcws device. Exercise-induced Delta[tHb] and Delta[Oxy] responses at each constant workload were evaluated as functional Delta[tHb] change (f-Delta[tHb]) and functional oxygenation change (f-Delta[Oxy]), respectively. Blood lactate concentration [La] was also evaluated after each exercise stage. RESULTS: At work rates 60%Wmax and below, after an initial decrease at the start of exercise, both Delta[tHb] and Delta[Oxy] showed progressive increases until the end of exercise. A significant positive correlation was found between f-Delta[tHb] and f-Delta[Oxy] (p<0.01). In addition, there was a significant negative relationship of [La] to f-Delta[tHb] during exercise (p<0.05). CONCLUSIONS: These results provide evidence that increased muscle oxygenation during bicycle exercise up to 60%Wmax may be caused by increased O2 supply due to exercise-induced blood volume expansion. Subsequently, the cessation of increase in f-Delta[tHb] at higher intensity exercise may lead to lower muscle tissue oxygenation and higher lactate accumulation.
    [Abstract] [Full Text] [Related] [New Search]