Apple Watch Fitness Icon Color Change

Yesterday my fitness icon changed from a green man to a red man. The exercise session starts with a green progressing circle, a green man, and green 1 .. 2 .. 3, now its a red progressing circle, a red man, and red 1 .. 2 .. 3. Following the exercise session you could find the walk in the iPhone fitness app listed by green distance walked, and now the walk is listed in the iPhone fitness app by red calories burned. I can find no documentation that instructs a user on how to make this change or reverse it. What did I touch that I shouldn't have touched. Thanks.