hyperventilation
He imagines conspiracies and starts hyperventilating.
I was with Jacob once when a fan was hyperventilating so much I thought she would faint.
We see a young woman practically hyperventilating with excitement.

SMART Vocabulary: related words and phrases

Respiratory disorders
allergic rhinitis
altitude sickness
anti-asthma
anti-tubercular
anti-tuberculosis
asthmatic
Covid-19
croup
double pneumonia
dyspnea
emphysema
farmer's lung
hacking
halitosis
SARS-CoV-2
shortness of breathphrase
sinusitis
sore throat
strep throat
stuffiness

You can also find related words, phrases, and synonyms in the topics:

Animal physiology: breathing & stopping breathing
Becoming too excited and easily upset