2 hours holotropic breathing alone dangerous or not?

[DVL]

I am interested what you guys think about  holotropic breathing doing for 2 hours? I am planning to do it alone, eyes closed and listening some music. Have done it for 1 hour and want to try for 2. How you guys think is it dangerous or not? Any advice will be helpful, thank you

Edited September 11, 2020 by DVL