Fitness App (free version) colors in workout display

When viewing a workout (such as a pool swim) in the Fitness app (free version) on my iPhone, the metrics such as time, distance, heart rate, etc. are displayed in different colors (e.g., times in yellow, distance in blue, calories in red, heart rate in orange, laps and pool length in purple. Do these colors have significance? E.g., is the heart rate in orange because it's too low?