the answer is none of the above.
Expected life events wont be as terrifying because you know they are coming unexpected life events could be deadly though cause i mean cancer is usually unexpected and it could go on for a while without you knowing. Hope this helps!
Answer: Aerobic Heart Rate Zone
This is the zone to aim for when training for endurance. It spurs your body to improve your circulatory system by building new blood vessels and increases your heart and lung capacity. Aiming for 20 to 60 minutes in this zone is believed to give the best fitness training benefits.