Should you incorporate aerobic exercise in your fitness program?

We can approach this question logically. We know that if we don't exercise our aerobic fitness will continue to decline as we age. To avoid this decline, some level of exercise should be included in our fitness regimens. This determination begins with a physical audit of your cardiovascular system. If there is no or little evidence of heart disease or high blood pressure than there should be no hesitancy to include aerobic work in your program. Even if there are some heart or lung problems, some modified exercise is still called for—perhaps not running but rather a walking or jogging regimen.
Aerobic training comes with some caveats. We know middle-age aerobic training will help maintain the elasticity of the heart. It is this elasticity that gives the heart much of its pumping ability. At some point in the aging process heart muscles harden and once this occurs it is difficult if not impossible to regain that elasticity. So the question is whether aerobic exercise should be included in a program for a new exerciser over 65?
Here is what I know.
The Covid crisis caused me to cut back on my aerobic exercise for over a year. When I resumed my interval training, I was shocked in the amount of deterioration in my aerobic fitness. I could not even complete a light version of my previous program. Halfway through the first workout, I had to stop. Because I am approaching my eighth decade, I was concerned. The good news is that I scaled back my program and in just few months I regained and surpassed my previous fitness level. Training works!
Supplying oxygen to all of the body’s cells plays a crucial role in maintaining cellular health. When the body loses its ability to deliver and process oxygen to the cells, the cells die; when cells die, organs die and when organs die, we die. The only way to retain this oxygen processing ability is through aerobic exercise. Is aerobic exercise important? Is living important?