In response to increased cardiorespiratory fitness, the factor that will decrease is resting heart rate.
1. **Resting Heart Rate:** When cardiorespiratory fitness improves, the heart becomes more efficient at pumping blood, which leads to a lower resting heart rate. This means the heart doesn't have to work as hard to supply the body with oxygen and nutrients at rest. Therefore, as cardiorespiratory fitness increases, resting heart rate decreases.
In summary, among the options provided, resting heart rate is the factor that will decrease in response to increased cardiorespiratory fitness.
