Fuelling cerebral activity in exercising man. Export

@article{citeulike:557037, abstract = {The metabolic response to brain activation in exercise might be expressed as the cerebral metabolic ratio (MR; uptake O(2)/glucose+1/2 lactate). At rest, brain energy is provided by a balanced oxidation of glucose as MR is close to 6, but activation provokes a 'surplus' uptake of glucose relative to that of O(2). Whereas MR remains stable during light exercise, it is reduced by 30\% to 40\% when exercise becomes demanding. The MR integrates metabolism in brain areas stimulated by sensory input from skeletal muscle, the mental effort to exercise and control of exercising limbs. The MR decreases during prolonged exhaustive exercise where blood lactate remains low, but when vigorous exercise raises blood lactate, the brain takes up lactate in an amount similar to that of glucose. This lactate taken up by the brain is oxidised as it does not accumulate within the brain and such pronounced brain uptake of substrate occurs independently of plasma hormones. The 'surplus' of glucose equivalents taken up by the activated brain may reach approximately 10 mmol, that is, an amount compatible with the global glycogen level. It is suggested that a low MR predicts shortage of energy that ultimately limits motor activation and reflects a biologic background for 'central fatigue'.Journal of Cerebral Blood Flow \&\#38; Metabolism advance online publication, 14 December 2005; doi:10.1038/sj.jcbfm.9600256.}, address = {1Department of Anaesthesia and The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.}, author = {Dalsgaard, Mads K K.}, citeulike-article-id = {557037}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/sj.jcbfm.9600256}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16395281}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16395281}, day = {14}, doi = {10.1038/sj.jcbfm.9600256}, issn = {0271-678X}, journal = {J Cereb Blood Flow Metab}, keywords = {fatigue, mri}, month = {December}, posted-at = {2006-03-20 14:12:44}, priority = {2}, title = {Fuelling cerebral activity in exercising man.}, url = {http://dx.doi.org/10.1038/sj.jcbfm.9600256}, year = {2005} }

TY - JOUR ID - citeulike:557037 L3 - citeulike-article-id:557037 N2 - The metabolic response to brain activation in exercise might be expressed as the cerebral metabolic ratio (MR; uptake O(2)/glucose+1/2 lactate). At rest, brain energy is provided by a balanced oxidation of glucose as MR is close to 6, but activation provokes a 'surplus' uptake of glucose relative to that of O(2). Whereas MR remains stable during light exercise, it is reduced by 30% to 40% when exercise becomes demanding. The MR integrates metabolism in brain areas stimulated by sensory input from skeletal muscle, the mental effort to exercise and control of exercising limbs. The MR decreases during prolonged exhaustive exercise where blood lactate remains low, but when vigorous exercise raises blood lactate, the brain takes up lactate in an amount similar to that of glucose. This lactate taken up by the brain is oxidised as it does not accumulate within the brain and such pronounced brain uptake of substrate occurs independently of plasma hormones. The 'surplus' of glucose equivalents taken up by the activated brain may reach approximately 10 mmol, that is, an amount compatible with the global glycogen level. It is suggested that a low MR predicts shortage of energy that ultimately limits motor activation and reflects a biologic background for 'central fatigue'.Journal of Cerebral Blood Flow & Metabolism advance online publication, 14 December 2005; doi:10.1038/sj.jcbfm.9600256. JF - J Cereb Blood Flow Metab SN - 0271-678X AD - 1Department of Anaesthesia and The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. TI - Fuelling cerebral activity in exercising man. KW - fatigue KW - mri AU - Dalsgaard, Mads K PY - 2005/12/14/ UR - http://dx.doi.org/10.1038/sj.jcbfm.9600256 ER -