Also, Doppler can detect abnormal blood flow within the heart, which can indicate a problem with one or more of the heart's four valves. Color Doppler. Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow.
Quick Answer. The age at which people grow armpit hair varies, but for boys it is often between the ages of nine and 14. Girls typically begin to grow this hair between eight and 13 years of age. Keep Learning.
On average a young man starts growing facial hair around 15 to 16 years of age. It starts in the fourth stage in Tanner's Stages of Puberty. Because boys start puberty at different ages and progress at different rates, it is considered normal to have facial hair as young as 11 or to not start developing facial hair until as late as 17. To estimate what stage of development you are in, see the Tanner Stage Calculator for Boys.