I usually workout for 50 mins. but at the end my ears react as if like low pressure.. same when we climb to a high altitude.. whts wrong..

You could have a: Blocked eustachian tube which connects the nose cavity with the middle ear. Follow up with your dr or an ENT specialist. Take care!

Dehydration?: You may be becoming dehydrated, and because of this change the dynamics of the eustacian tubes which run from the middle ear to the back of throat, causing a pressure sensation in the middle ear. If this continues try drinking lots of liquid during the workout and see if it makes a difference. If not, see an ENT doctor. Good luck, hope you get this resolved.