Definitions for "grueling"
characterized by toilsome effort; requiring extreme physical or mental effort; as, a grueling campaign.
characterized by toilsome effort to the point of exhaustion; especially physical effort; "worked their arduous way up the mining valley"; "a grueling campaign"; "hard labor"; "heavy work"; "heavy going"; "spent many laborious hours on the project"; "set a punishing pace"
(adj) – Physically or mentally demanding to the point of exhaustion