Heart disease and cancer are two of the top killers of Americans, and exercise can effectively help prevent the onset of both, primarily by normalizing your insulin and leptin levels.
Other beneficial biochemical changes also occur during exercise, including alterations in more than 20 different metabolites. Some of these compounds help you burn calories and fat, while others help stabilize your blood sugar, among other things.
In a nutshell, being a healthy weight and exercising regularly creates a healthy feedback loop that optimizes and helps maintain healthy glucose, insulin and leptin levels through optimization of insulin and leptin receptor sensitivity.
And, as I've mentioned before, insulin and leptin resistance—primarily driven by excessive consumption of refined sugars and grains along with lack of exercise—are the underlying factors of nearly all chronic disease that can take years off your life.
Previous research has shown that exercise alone can reduce your risk of cardiovascular disease by a factor of three.4 However, endurance-type exercise, such as marathon running, can actually damage your heart and increase your cardiovascular risk by a factor of seven...
Research5 by Dr. Arthur Siegel, director of Internal Medicine at Harvard's McLean Hospital found that long-distance running leads to high levels of inflammation that can trigger cardiac events. Another 2006 study6 found that non-elite marathon runners experienced decreased right ventricular systolic function, again caused by an increase in inflammation and a decrease in blood flow.
All in all, such findings are a powerful lesson that excessive cardio may actually be counterproductive. In the featured review, the types of exercise, frequency, intensity and duration varied widely across the included studies, which made it impossible to ascertain the specifics of what was most or least effective for the prevention and treatment of disease.
However, it was clear that exercise in general is comparable to many of the drugs used for heart disease, heart failure, and stroke. That said, other research has clearly demonstrated that short bursts of intense activity is safer and more effective than conventional cardio—for your heart, general health, weight loss, and overall fitness. One of the easiest ways to exercise is simply by performing body weight exercises.