The paper analyzes the effect of acute hypoxia to dissonant intervals at the speech signal. It presents the factors that lead to the hypoxia as a consequence of the oxygen concentration decrease in the tissue. Furthermore, a definition of dissonant spectrum ranges of the speech signal is determined. It is made in relation to the fundamental frequency. It stands as tones' F#, B and C# in relation to C. For the experiment, the articulation of vowels from the group of persons was recorded. It is performed at 200, 800, 1400 and 1900 m altitudes above the sea level. The result of this speech signal testing is summarized and shown in graphs. Furthermore, the dissonant coefficient k_F#, k_B and k_C#, have also been determined. Their values indicate the degree of the acute hypoxia.

Key words: Speech signal, fundamental frequency, dissonant frequency, acute hypoxia.