“
When it comes to cardiovascular exercise, the general guidelines recommend doing between 20 and 60 minutes. However, this will depend on the intensity of the exercise you are doing. Steady state low intensity cardio, such as walking on a treadmill, can be done for up to an hour at a time. In contrast, high intensity interval training (HIIT), which involves short sprints followed by even shorter rest intervals, should only last for a maximum of 20 minutes.
”
”
Nick Swettenham (Total Fitness After 40: The 7 Life Changing Foundations You Need for Strength, Health and Motivation in your 40s, 50s, 60s and Beyond)