1. Water
Water is not a macronutrient because water has no calories
Participating in extreme sports can help your cardiovascular system work properly and better because extreme sports usually are very taxing in terms of being an aerobic sport which also puts a lot of burden on the aerobic system. Another benefit would be not so health-related but more personal; doing extreme sports and being close to death - which can hppen - makes one more appreciative and aware of life and death.
Answer:
Subtract your heart's resting rate from your maximum rate. For example, if you are 40 years old, subtract that number from 220; your maximum rate is 180. Next, subtract your resting rate or 80 in this example. Your heart-rate reserve is 100 beats per minute.