Curcumin has potent anti-inflammatory properties that can potentially blunt adaptation responses to exercise.

“curcumin is known to have very potent anti-inflammatory properties I don't think that's debated at all in fact it's so potent as an anti-inflammatory that some people have cautioned against taking high levels of curcumin prior to for instance resistance training workouts or even cardiovascular workouts because it so prevents inflammation that it also can prevent the adaptation response”