Interval Cardio

I didn't go as hard as the last time but intense nonetheless. My cardiovascular conditioning is improving by the day and I've noticed it's getting a little harder getting my heart rate up to certain levels.

Previous

Duration: 30:01
Calories: 379
Average Heart Rate: 152 bpm (80% MHR)
Maximum Heart Rate: 180 bpm (95% MHR)
Fat Percentage of Calories: 12%

Tonight

Duration: 30:01
Calories: 346
Average Heart Rate: 146 bpm (77% MHR)
Maximum Heart Rate: 171 bpm (90% MHR)
Fat Percentage of Calories: 14%