Dear sir my hb level is 17.8 now. this is creating any risk? how can i reduce plz

This level of: hemoglobin is only slightly elevated; normal for men is up to 17.5 g/dl. Two of the most common causes of slightly elevated hemoglobin is smoking and living at higher altitude: red blood cell production compensates for lower oxygen supply. Other causes include poor heart or lung function, bone marrow dysfunction, certain drugs or hormones...not high enough to cause problems but the cause might be