After Frida stops exercising, she continues to breathe heavily. What is most likely occurring in her body?

Hey there,

So since Frida was just exercising her body was pumping blood to supply oxygen faster at a higher rate, therefore, now that she's stopped her body has to once again get used to the rapid change in oxygen reliance and is slowing itself down meaning that she needs to breathe more and longer

Strenuous exercise has caused her body to be in oxygen debt, and she is breathing hard while lactate is transported to the liver. This is a result of anaerobic respiration.