When ascending sometimes my dive buddy gets nosebleeds. Why does this happen? and should it be of any concern to him?

Yes! Any physicle condition out of the ordinary while diving should be accessed by a doctor qualified in dive medicine.

Give the Divers Alert Network experts a call at the numbers below. These are physicians that deal specifically with researching diving physiology and can answer your inquiries about this type of condition better than anyone else around. Your friend may wish to consult with them in order to find a local ENT (Ears, Nose Throat) specialist that is specialized in diving medicine

Non-Emergency Medical Questions
1-800-446-2671 or 1-919-684-2948, Mon-Fri, 9am-5pm (ET)

chances are your buddy is squezzing his nose to hard as he equalized., or is equalizing wrong . when in doubt
call DAN and they will answer you and give you the right medical answer