physiological; physical
Refers to biological or bodily functions and processes, often in medical or scientific contexts.
Sweating is a physiological response.
Sleep is a physical necessity.
visceral; instinctive; gut-level
Describes a deep, almost bodily reaction or feeling that is not based on logic; often used for strong dislikes or aversions.
I have a visceral dislike for his attitude.
I instinctively can't stomach that food.
I have a gut-level aversion to insects.
I just can't stand him on a gut level.
An increased heart rate under stress is a physiological reaction.
Appetite and the need for sleep are examples of physiological needs.