People that die of heart disease well there is normally a predisposed genetic condition via family history that effects a large amount of people and all the cardio in the world will not fix it.
That's simply not true:
https://www.heart.org/HEARTORG/Heal...cal-Activity-in-Adults_UCM_307976_Article.jsp
Cardiovascular disease like heart disease, strokes and diabetes are all linked to a few factors, primarily something called metabolic syndrome. Metabolic syndrome is a combination of high bloodpressure, insulin resistance, high bloodsugar, abdominal fat and high LDL cholesterole. All this creates ateroschlerosis which is basicly a hardening of the artieries and forming of plaque (blood clots). Aneurysms can happen, blood clots can form and travel to the coronar arteries causing myocardial infarct (lack of blood to the heart muscle and subsequently neocrosis or death of cells). Most heart diseases starts as something called angina pectoris, either stable or unstable, which is because of clogged arteries. Blood clots can also travel to the brain and cause strokes and such. I wont go too far into it, but aerobic fitness is important in that regard. There's too major reason why aerobic exercise is preferable, most of the time, over HIT or heavy lifting for cardiovascular health. One is blood pressure.
High blood pressure over time harms the arteries and the endothel cells they are made of, making blood clots easier to form. Blood pressure: BP = Q x PR, meaning volume of blood pr minute (Q) and the resistance in the arteries (PR). High blood pressure increases the plaque in the arteries over time, increasing the blood pressure even more. HIT training and heavy lifting increases blood pressure. Aerobic conditioning lowers it, not only temporary, but also because of this second and important adaption. Hypertrophy of the heart.
There's two primary forms of hypertrophy of the heart. One is that the left ventricle walls thicken and becomes better at forcefully pumping blood out. This happens more with high blood pressure, meaning HIT and heavy lifting. This improves the hearts ability to pump blood out with greater pressure, but in turn the ventricle (the lower heart chamber) has less space in which to fill the heart with blood and less time to do so. This results in a heart that has to work more and harder to pump equal volume, and in turn, a heart that is working overtime.
The second form is the expansion of the left ventricle. This happens more with aerobic training, as the heart is filled properly with blood each time and with less pressure, and adapts to filling more efficiently. Aerobic training also increases the percentage of blood plasma, vs bloodcells, and therefor the resistence of the arteries is less, hence lower bloodpressure. This is the foundation of endurance.
This post is already long enough, but now you understand some of the very basic physiological differences. It's not black and white, but being active for longer periods of time is important for health.
