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.
(I got armpit hair around 11 1/2 but everyone is different) From around age 13-16 but it can still happen earlier or later (maybe even 12 and 19) got mine just before i turned 14. Brent Lyday.
Though boys typically begin puberty between the ages of 9-14 (commonly ends at the ages between 16-18) and the changes of puberty follow a pattern, every boy develops at his own pace. If you want to know if you have hit puberty, just follow these steps.