For example, during periods of exertion the body rapidly breaks down stored carbohydrates and fat, releasing CO2 into the blood stream.
fɔːɹ ɛɡzˈæmpəl, dˈʊɹɹɪŋ pˈiəɹɪədz ʌv ɛɡzˈɜːʃən ðə bˈɑːdi ɹˈæpɪdli bɹˈeɪks dˌaʊn stˈoːɹd kˌɑːɹboʊhˈaɪdɹeɪts ænd fˈæt, ɹᵻlˈiːsɪŋ sˌiːˈoʊ tˈuː ˌɪntʊ ðə blˈʌd stɹˈiːm.