Heart rate zones

Hello,

I would like to see my heart rate with color (blue = warm up, green = fat burning, yellow = aerobic, orange = anaerobic, red = extreme) depending on zone I am in. The gauge would also show current percentage of the zone like it is shown on the tiny bar in the power values.

Why? For example when trying to lose weight, it is recommended to train in the 65-75% of HRmax. And where from should we get the current heart zones? Either by calculating them from well-known formula based on gender, weight, age but tha would mean additional data in user profile. Or better, set the zones (HR from A to B = Zone 1, from C to D = Zone 2 and so on) so every one would calculate/set them individually by own favorite calculation method.