The physiological effects of IFC  include:

an increase in localized blood flow which can improve healing by reducing swelling and as a result helps remove damaged tissue and bring nutrients necessary for healing to the injured area.

The stimulation of local nerve cells that can have a pain reducing/anaesthetic effect.

Also, it helps to stimulate of local nerve cells that can have a pain reducing/anaesthetic effect due to potentially blocking the transmission of the pain signals (pain gate mechanism) or by stimulating the release of pain reducing endorphins.