Since someone would be performing wind sprint activities, it is guaranteed when performing any activity is to get better overtime so I would say to "work above your target heart rate"
<span>By using FITT principles, my cousin’s goal for his cardiovascular system and fitness levels will be achieve for an improvement will be observe. Running three times per week and gradually increasing to five times a week for cardio-vascular fitness is very effective after three months. Moreover, these changes will be monitor with heart rate monitor and a weighing scale.</span>
I am pretty sure that is true