Hyperventilating

Tom's hyperventilating.

Tom seems to be hyperventilating.

Tom is hyperventilating.

Tom was so out of shape that he couldn't run a lap around the block without hyperventilating.

Ziri was shaking and hyperventilating.

Flavio was hyperventilating.

Tom was hyperventilating.

Janos started hyperventilating.

The patient is hyperventilating.