2.64 explain how the heart rate changes during exercise and under the influence of adrenaline

 There is a higher demand for oxygen and glucose during exercise so it must be supplied to the respiring cells quicker: circulation rate must increase and the heart will have to pump harder and faster

Under the influence of adrenaline, the heart rate (bpm) increases, this supplies extra blood and oxygen to the muscles which his enables them to release extra energy. The fight or flight response is triggered by adrenaline