Does the human body grow while sleeping?

sleeping can actually promote growth in your body and without proper sleep you might not grow taller.
The more fluid in your joints the taller you will grow. This is why gravity is your biggest enemy when trying to grow taller since it will pull on your body while you're in an upright position and squeeze the fluids out your joints by compressing them. So during the day while you're in an upright position gravity will cause your body to shrink by squeezing fluids out your joints.
Laying down counters that gravity! Sleeping helps you grow!