We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
I have posted most of these concepts in the past, but it's time to revisit them.
First off, people use the term to refer to different things. Some use it to refer to anything that raises your heart rate at all, such as walking, hiking, or swimming aerobic laps. Anything we do to remain active, if not to reach for better levels of fitness, is worthwhile.
Why is low-intensity activity worthwhile? Because it helps maintain a current level of function. Keep walking 1-3 miles daily, and odds are you will keep doing it until something physical intervenes. That's all that most people want.
However, I think of "cardio" as heart-centered exertion. That means stressing the heart with the goal of improving fitness and conditioning. While my favorite forms of cardio (treadmill, stair machine, rower) keep many muscle groups busy if not stressed, the goal is cardiac muscle power. That is why cardio focus is almost 1/3rd of the Maggie's Fitness for Life program.
How do you stress your heart muscle, rather than just using it a little bit? By making high demands just as you can do with other muscles. That means sprints on your favorite "cardio" forms. That's assuming your doctor tells you that you are fit for intensity.
Regardless of the exercise, it's easy to know when you are sprinting because it's all-out for 30-60 seconds at intervals. That is HIIT. Sprints are anaerobic, not aerobic. People claim that heavy weight-lifting can have the same effect, and that is likely true. Still, I feel a couple of hours/week of HIIT cardio is a good supplement, plus endurance, plus mental health.
Daily running hill climb at the community park.
Keep plugging at the top even with increased heart rate and burn in the calf muscles with two laps of brisk walking around the flat paved course.
No breaks until seated in vehicle with a water waiting in the drink holder.