Are noseband pressures constantly high?
The simple answer is no, if the noseband is “correctly” fitted!
If the noseband is fitted correctly, the noseband pressures are of a magnitude that should not cause any pain or discomfort. Noseband pressures are cyclical, meaning that within the stride cycle, they have a maximum and minimum value. The peaks and troughs are repeatable and occur during the early part of the stance phase. For a correctly fitted noseband, the magnitude of minimal pressure is very low; it should be noted that pressure beneath the noseband only occurs when the horse pushes against it; at all other times, the pressures are close to zero.
Further reading and watching:
Bridle fitting guidelines: https://www.worldhorsewelfare.org/advice/bridles-how-to-choose-and-fit-them-correctly?srsltid=AfmBOorOGLfgrP_MimX8-AxVG_gIOLRm7mk8I4XoNuYvC-aw7RoAcyrK
Bridle fitting webinar with Dr Rachel Murray: https://www.youtube.com/watch?v=L1j3gnKFGNo