hy ‧ per ‧ ven ‧ ti ‧ late /ˌhaɪpəˈventəleɪt, ˌhaɪpəˈventɪleɪt $ -pərˈventl-eɪt/ BrE AmE verb [intransitive]
to breathe too quickly or too deeply, so that you get too much ↑ oxygen and feel ↑ dizzy
—hyperventilation /ˌhaɪpəventəˈleɪʃ ə n, ˌhaɪpəventɪˈleɪʃ ə n $ -pərventlˈeɪ-/ noun [uncountable]