Docstoc

Effect of lower limb exercise on forearm blood flow_ Contribution

Document Sample
Effect of lower limb exercise on forearm blood flow_ Contribution Powered By Docstoc
					             Effect of lower limb exercise on forearm blood flow: Contribution of nitric oxide?

                      D.J. Green*1,2, L. Mavaddat1, C. Cheetham1,2, K. Watts1, M. Best2 & J.G. O’Driscoll2
                           1
                             Department of Human Movement and Exercise Science UWA, Australia
                                   2
                                     Cardiac Transplant Unit, Royal Perth Hospital, Australia


Nitric oxide (NO) contributes to vasodilation in active tissue beds. However, there have been no studies of NO release in inactive vessel beds
during exercise. Eight male volunteers were randomised to participate in two studies, each consisting of two bouts of lower limb exercise
separated by 30 min rest. Each exercise bout involved five epochs on a bicycle ergometer. During one study, the brachial artery was cannulated
to allow saline infusion during the initial exercise bout and L-NMMA, an inhibitor of NO, during the repeat. The alternate study provided a control
for the effects of repeated exercise. Resting forearm blood flow (FBF), obtained from synchronised ultrasound and Doppler, increased incrementally
during lower limb exercise and was higher at all exercise intensities when compared to baseline data (p<0.01). At higher levels of exercise
intensity L-NMMA significantly decreased FBF (p<0.05), indicating that NO contributed to the increase in FBF. Prior exercise had no effect on
hyperaemic responses during the repeat exercise bout on the non-infusion day. This data indicates that enhanced systemic production of NO
occurs during exercise. The results of this study provide a possible explanation for the cardioprotective effects of exercise as NO possesses
potent anti-atherogenic and thromboresistant properties.




                                                                             Print           Index          Table of Contents                Quit
   Effect of lower limb exercise on forearm blood flow: Contribution of nitric oxide?
                               D.J. Green*1,2, L. Mavaddat 1, C. Cheetham1,2, K. Watts1, M. Best2 & J.G. O'Driscoll2
                                    1Department of Human Movement and Exercise Science UWA, Australia
                                            2Cardiac Transplant Unit, Royal Perth Hospital, Australia



    Nitric oxide (NO) contributes to vasodilation in active tissue beds. However, there have been no studies of NO release in
inactive vessel beds during exercise. Eight male volunteers were randomised to participate in two studies, each consisting of two
bouts of lower limb exercise separated by 30 min rest. Each exercise bout involved five epochs on a bicycle ergometer. During
one study, the brachial artery was cannulated to allow saline infusion during the initial exercise bout and L-NMMA, an inhibitor of
NO, during the repeat. The alternate study provided a control for the effects of repeated exercise. Resting forearm blood flow
(FBF), obtained from synchronised ultrasound and Doppler, increased incrementally during lower limb exercise and was higher
at all exercise intensities when compared to baseline data (p<0.01). At higher levels of exercise intensity L-NMMA significantly
decreased FBF (p<0.05), indicating that NO contributed to the increase in FBF. Prior exercise had no effect on hyperaemic
responses during the repeat exercise bout on the non-infusion day. This data indicates that enhanced systemic production of NO
occurs during exercise. The results of this study provide a possible explanation for the cardioprotective effects of exercise as NO
possesses potent anti-atherogenic and thromboresistant properties.

				
DOCUMENT INFO
Shared By:
Tags: Limb, exercise
Stats:
views:4
posted:7/19/2011
language:English
pages:2
Description: Lying down, arms and legs slightly apart, palms turned to the ceiling, eyes closed, breathe deeply three times, concentrate on each breath completely empty flat body. Then from the toes to the head, tighten and then relax the muscles a little bit, carefully to feel every step. For the shoulder and head muscles, use the rotation instead of tightened. This is a developing body flexibility and effective practice, with a strong relaxation of, but also to ease the tension.