I am a morning person with lots of energy once I wake up. I am a heavy sleeper who does not wake up easily. When I was young I was a light sleeper, even the slightest noise woke me up.

A morning person is a person who wakes up early in the morning with energy and does a lot of things. A night person is a person who stays awake late at night but remains very productive. A light sleeper is a person who does go to sleep but wakes up at the slightest noise. (Wakes up easily).

A morning person is one who is awake very early in the morning, mostly before sunrise. A night person is usually awake during the very late hours of night. And a light sleeper is one who falls asleep, but can be woken up easily by noises, or to lights being turned on.

爱早起的人，夜猫子，易醒的人

light sleeper might mean for those who get used to turn on lights when he / she sleeps. Light sleeper可能是说晚上习惯不关灯睡觉