High Intensity Definition

May be a silly question, but at what percent of Ftp is an interval considered a high intensity interval? Is sweet spot considered high intensity? I can’t find a definition.

If i remember right i would concider 75-94% as medium intensity, above high and below low.

95% and up. Sweetspot takes up the spectrum of 88-94%.

My own definition would rather be if I’m in the threshold-zone H/R-wise then I’m doing high intensity-work.