What is the high intensity cardiorespiratory training zone for a 20 year old with resting heartrate of 68?

To calculate the high-intensity cardiorespiratory training zone for a 20-year-old with a resting heart rate of 68, you can use the Karvonen formula:

$$\texttt{Target Heart Rate} = \texttt{Resting Heart Rate} + (\texttt{Maximum Heart Rate} - \texttt{Resting Heart Rate}) \times \texttt{Intensity}$$

Where:

- \(\texttt{Maximum Heart Rate}\) is estimated as 220 - age.

Therefore \(\texttt{Maximum Heart Rate}\) is 152 bpm.

- \(\texttt{Intensity}\) is between 0 and 1, where 0 represents no exercise and 1 represents maximal exercise.

Calculating the High Intensity Zone (generally considered between 70% to 85% intensity):

- Calculate the low end target: 68 + (152 - 68) x 0.70 = 132 bpm

- Calculate the high end target: 68 + (152 - 68) x 0.85 = 146 bpm

Therefore, the high-intensity cardiorespiratory training zone for the individual would be between 132 and 146 beats per minute. This zone is typically reached during vigorous exercise such as running, cycling, or swimming, where the heart rate is elevated and sustained for a prolonged period of time.