A little adrenaline sharpens focus; too much narrows it until you're re-reading the same sentence three times. The goal isn't to eliminate nerves before a board exam, it's to keep them at a level where they still help.
Name what's actually causing it
Vague dread is harder to manage than a specific worry. Write down the two or three things you're actually afraid will happen, then check which of them you've already prepared for. Most of the fear turns out to be about scenarios your practice has already covered.
Rehearse the format, not just the content
Unfamiliar interfaces add stress on top of content stress. Running full-length timed blocks in a format that matches the real exam removes one entire category of surprise from test day.
Build a short reset routine
Pick a brief, repeatable action — a breathing count, a stretch, a specific phrase — and use it every time you sit down to a timed block during prep. By exam day it's a cue your body already recognizes.