To improve your cardiovascular fitness: A. Include a minimum of 20-30 minutes of aerobic activity 3-4 times a week.
B. Use weights or resistance to build your muscles.
C. Perform push ups and curl ups daily.
D. Stretch every day.

People who utilizes the progression principle will ensure their exercise program increases in frequency, intensity, time, and type. the changes need to happen gradually in order to ensure they make gains in their fitness program. a person who doesn't utilize the progression principle can still gain health benefits from exercising, but will not continue to improve in cardiovascular fitness.