There are several alternative phrases that can be used instead of "adrenaline really kicks in" to express a similar feeling of excitement or heightened alertness. Some options include "my heart starts racing," "my blood pumps faster," "my senses sharpen," "I feel a rush of energy," "my nerves become tingling," and "I get a burst of excitement." Each of these phrases conveys the idea that the body is preparing for action, whether it's due to fear, excitement, or both. No matter which synonym is used, the underlying feeling is one of anticipation and readiness for whatever comes next.