Is it normal for everything to sound like it's underwater after a strenuous workout?

This is something that's been bugging me for a long time. Everytime I really push myself in a workout whether it be cardio, or even just lifting, when my heart rate gets high and I start sweating a lot, my ears will make things sound different, like my breathing becomes very audible, as if I was underwater and I was holding my hands over them, my voice is amplified greatly, everything just takes on a highly amplified tone that usually corresponds with deep breaths, however, under vigorous workouts, it becomes continuous for about an hour...is this normal? What causes this?