Congrats on your increased performance. Going faster and further is the bottom line. Well done.
Many, many things affect heart rate. It may go up or may go down but it is not a measure of performance. An increase in cardiovascular fitness can be reflected as a lower heart rate. Your heart is stronger and oxygen delivery system more efficient thus it needs to beat fewer times per minute to deliver the required fuel to the muscles.
Some athletes are not good test takers…you may be one of them. Increased performance can be observed in areas other than a test.
Lynda