Editing Exercise physiology (section)

=== Glucose ===
In adults, exercise depletes the plasma glucose available to the brain: short intense exercise (35 min ergometer cycling) can reduce brain glucose uptake by 32%.<ref name="Pmid">{{Cite journal |last=Kemppainen |first=J |last2=Aalto |first2=S |last3=Fujimoto |first3=T |last4=Kalliokoski |first4=KK |last5=Långsjö |first5=J |last6=Oikonen |first6=V |last7=Rinne |first7=J |last8=Nuutila |first8=P |last9=Knuuti |first9=J |year=2005 |title=High intensity exercise decreases global brain glucose uptake in humans |journal=The Journal of Physiology |volume=568 |issue=Pt 1 |pages=323–32 |doi=10.1113/jphysiol.2005.091355 |pmc=1474763 |pmid=16037089}}</ref>

At rest, energy for the adult brain is normally provided by glucose but the brain has a compensatory capacity to replace some of this with [[lactic acid|lactate]]. Research suggests that this can be raised, when a person rests in a [[Positron emission tomography|brain scanner]], to about 17%,<ref>{{Cite journal |last=Smith |first=D |last2=Pernet |first2=A |last3=Hallett |first3=WA |last4=Bingham |first4=E |last5=Marsden |first5=PK |last6=Amiel |first6=SA |year=2003 |title=Lactate: A preferred fuel for human brain metabolism in vivo |journal=Journal of Cerebral Blood Flow and Metabolism |volume=23 |issue=6 |pages=658–64 |doi=10.1097/01.WCB.0000063991.19746.11 |pmid=12796713 |doi-access=free}}</ref> with a higher percentage of 25% occurring during [[hypoglycemia]].<ref>{{Cite journal |last=Lubow |first=JM |last2=Piñón |first2=IG |last3=Avogaro |first3=A |last4=Cobelli |first4=C |last5=Treeson |first5=DM |last6=Mandeville |first6=KA |last7=Toffolo |first7=G |last8=Boyle |first8=PJ |year=2006 |title=Brain oxygen utilization is unchanged by hypoglycemia in normal humans: Lactate, alanine, and leucine uptake are not sufficient to offset energy deficit |journal=American Journal of Physiology. Endocrinology and Metabolism |volume=290 |issue=1 |pages=E149–E153 |doi=10.1152/ajpendo.00049.2005 |pmid=16144821 |s2cid=8297686}}</ref> During intense exercise, lactate has been estimated to provide a third of the brain's energy needs.<ref name="Pmid" /><ref name="Dalsgaard, M. K. 2006">{{Cite journal |last=Dalsgaard |first=MK |year=2006 |title=Fuelling cerebral activity in exercising man |journal=Journal of Cerebral Blood Flow and Metabolism |volume=26 |issue=6 |pages=731–50 |doi=10.1038/sj.jcbfm.9600256 |pmid=16395281 |s2cid=24976326}}</ref>  There is evidence that the brain might, however, in spite of these alternative sources of energy, still suffer an energy crisis since IL-6 (a sign of metabolic stress) is released during exercise from the brain.<ref name="Nybo, L. 2005" /><ref name="Secher, N. H. 2008" />