When you're exhausted Adrenaline activates you get exhaustion for 60/50/40 seconds no matter what, but Blood Echo gives you exhaustion for 45 seconds. What would happen if you had more than 45 seconds of exhaustion left and Blood Echo activates?
Before I can answer this question, note that there are two different types of Exhaustion effects:
- Timed effects
- These are caused by the survivor Sprint Burst; Balanced Landing; Lithe; Dead Hard; and Adrenaline perks, Huntress's Toxin addons, Clown's Solvent Jug addon, and the killer Blood Echo perk
- Permanent effects until a condition is resolved
- These are caused by the Doctor's "Obedience" addon, Doctor's Iridescent King addon, Pig's Slow-Release Toxin addon, Demogorgon's Lifeguard Whistle addon, and the killer Mindbreaker perk
As far as I can tell, these two types are tracked separately.
If you have a timed Exhaustion effect and would gain another timed Exhaustion effect, you will keep whichever timer is longer.