During exercise, increase in O2 delivery to muscles is because of all except
Oxygen dissociation curve shifts to left
Increased stroke volume
Increased extraction of oxygen from the blood
Increased blood flow to muscles
Hb-O2 dissociation curve shift to left indicates more affinity of Hb to O2 and thus less delivery of O2 to tissues. Exercise causes increased 2,3 DPG.
Shift to left seen in
-        Increased pH
-        Decreased 2,3 DPG, temperature, PCO2
-        HbF (Fetal)
Shift to right seen in
-        Decreased pH
-        Increased 2,3DPG, temperature, PCO2
-        HbS (Sickle cell)