I just got my Hac 4 and was reviewing the data. I'm not aerobically fit and weight 218lbs I have another 25lbs to loose. I am 39 years old. I set my upper HR limit at 180 and my lower at 133. When I look at the heart rate percentages the graph says 54% of my ride was done anaerobically and 35% was done in the base zone. From what I read this is not good for training. If I ride and do even small hills my HR goes between 150 and 175. What kind of riding should I do to improve my fittness?