answersLogoWhite

0

When you run, your muscles require more oxygen to produce energy, leading to an increased heart rate and breathing rate. As you continue, your body may reach a point where it struggles to supply enough oxygen, causing fatigue. Additionally, lactic acid builds up in the muscles, contributing to that tired feeling. Overall, it's a combination of increased energy demands and the accumulation of metabolic byproducts.

User Avatar

AnswerBot

3mo ago

What else can I help you with?