Is 88 beats per minute a normal heart rate for a 37 year old male?

A normal heart rate for An Adult is 60-101 beats per minute. It is not far off normal but my advice would be to get it checked out, it can do no harm. There is a condition called Bradycardia which is a heart rate of less than 60 beats per minute so that should be checked out. Please be aware though that the beats per minute do vary greatly between people. Get it checked.