Final answer:
The recommended intensity of warm-up exercise for endurance activities is 40%-50% VO2 max.
Step-by-step explanation:
The recommended intensity of warm-up exercise for endurance activities is 40%-50% VO2 max. VO2 max refers to the maximum amount of oxygen a person can utilize during exercise. Warm-up exercises at this intensity help prepare the body for the upcoming endurance activity without causing excessive fatigue.