ɐ hˌaɪpoʊpnˈiː ˈɪndɛks ˌeɪtʃˈaɪ kæn biː kˈælkjʊlˌeɪɾᵻd baɪ dᵻvˈaɪdɪŋ ðə nˈʌmbɚɹ ʌv hˌaɪpoʊpnˈiː ᵻvˈɛnts dˈʊɹɹɪŋ ðə slˈiːp pˈiəɹɪəd baɪ ðə nˈʌmbɚɹ ʌv ˈaʊɚz ʌv slˈiːp.
A Hypopnea Index (HI) can be calculated by dividing the number of hypopnea events during the sleep period by the number of hours of sleep.