What happen to your exploratory reserve volume when you are treading water in a lake?

When you are treading water in a lake, your exploratory reserve volume, which refers to the extra lung capacity available for deep breaths, remains relatively unchanged. However, your body may utilize more oxygen due to the physical effort of treading. This activity can lead to a slight increase in breathing rate, but the overall reserve volume itself does not significantly decrease unless you are exerting yourself for an extended period without adequate oxygen intake.