[normie3000]

During the run their heart rate will be higher, but afterwards their resting rate might be lower.

[antisthenes]

Right, that was the question.

Is there a net benefit?

[import]

There is a net benefit. Your heart gets stronger and spends less effort for pumping out the blood.

Your resting HR becomes lower and blood has more oxygen. And this happens 24/7. Assuming you’re running 5K 2 times in a week.