Cardiovascular Fitness 101

To be simply put, cardiovascular fitness is the ability of the heart-lung-blood system to supply oxygen to the working muscles during bouts of physical activity. This is also called aerobic capacity.

There are two factors which determines who has more aerobic capacity:

-Duration of the activity

-Intensity of the activity

Which means to say that the longer the duration and/or the higher the intensity, the better is the aerobic capacity.

Easy? Simple?

But that is where the similarities ends between real cardio training and nonsense cardio training.

I am going to introduce you an objective measure of aerobic capacity: VO2max. This is the maximal rate of oxygen used in physical activity. In the lab, the movement usually tested is running on a treadmill, at an increasing intensity. The higher the intensity that the person can sustain, the higher is the VO2. At maximal intensity, that is the VO2max.

Now do you see how the majority of people's idea of cardio is faulty?

Faulty logic #1: Confusing intensity with duration

VO2max is dependent on intensity, not duration. So why do people try to improve "cardio" through long-slow-distance (LSD) cardio? No matter how long the duration of your training is, if it does not come near your VO2max, it would not elicit an adaptation. Remember Specific Adaptation to Imposed Demands (SAID)?

What you really want in training is to improve duration of a high intensity effort.

Anybody can squat once. But can you squat 500 reps in 15 minutes?

Note: Hindu squat can be tough on your knees, do normal bodyweight squats instead.

Anybody can do a push up. But can you push up 2,354 reps in 30 minutes?

If you are training to improve duration at a submaximal intensity, you would want to improve what is called lactate threshold (LT) or anaerobic threshold, which is the ability of the body to clear lactic acid, ie delay the "burn" in your muscles. Anyway training to improve LT is also high intensity (Ha!). It is not maximal intensity however. But i won't go into further details on LT now.

Faulty logic #2: Using running as the BEST aerobic exercise

Notice that in the definition of VO2max, there is no restriction on what is the movement to use. A max is a max. In running, only the muscles of the lower body are the prime movers. And if you are familiar with the Pose Method of Running. Proper running technique is very efficient, ie uses little energy.

If you can involve your whole body to be prime movers of the movement, then doesn't it make more sense to increase your intensity and therefore VO2?

Do you know that the best VO2max records of any athlete in the world is held by a cross country skier (!). And if you see the table more carefully, XC skiers take up the upper half of the table, runners the lower half.

And that athletes of a short distance of 1500m can be in the top few rankings too.

Conclusion

Aerobic capacity is the ability of the heart-long-blood system to supply energy to the working muscles. If you can demand more energy from the system and it can supply you that demand, then you have a better aerobic capacity. To demand more, use as much muscles as possible in the training.