Decreased glycolytic activity impairs oxygen transport by hemoglobin due to
Decreased production of 2,3-bisphosphoglycerate 

2, 3 DPG is produced by an alternative pathway in glycolysis.
If the glycolytic activity is decreased, the levels of 2,3 - DPG in RBCs will decrease.
Decreased level of 2,3 - DPG causes:-


Shifts the oxygen-hemoglobin curve to the left
Increases the oxygen affinity of hemoglobin.
Reduced energy production
Decreased production of 2,3 - bisphosphoglycerate
Reduced synthesis of hemoglobin
Low levels of oxygen