Heart disease and cancer are the top two killers of Americans. Exercise can help in the battle against these two diseases – but what type of exercise and how much is advisable?

The journal “Progress in Cardiovascular Diseases stated that, “Natural selection shaped the human genome not to run marathons or exclusively lift extremely heavy weights but rather to survive and thrive as very active outdoor generalists in the wild.” What this means is people need to do a variety of exercises, not only for the prevention of chronic diseases, but to increase fitness as well.

To reap the benefits of exercise, according to the American College of Sports Medicine, it must be “tough.” That means discomfort. What it doesn’t mean is excruciating pain. Pain is the body’s way of warning you of possible injury. If you have pain while performing a certain exercise stop or modify the movement.

One type of exercise that is tough and gets the heart rate elevated is intervals. Intervals are often the centerpiece of training programs in sports. For many the word “intervals” sends shivers down their spines as this type of exercise (hard anaerobic effort followed by a short recovery time and then the hard effort is repeated) is challenging.

People mistakenly believe that intervals are only necessary for athletes and not for the person looking to get into shape. However, studies have shown that this challenging type of exercise not only makes you faster, it has been shown that high intensity workouts also burn the most fat calories, as well as total calories, in comparison to a low intensity effort. So if you’re looking to lose some weight an interval session, one to two times a week, should be part of your routine.

The moral of the story is fitness and good health doesn’t come easy or everyone would be in great shape. You need to push yourself and “feel the burn.” One of those ways to elevate the heart and burn the calories is a HIIT class. The short, intense efforts using different muscle groups, followed by a short recovery, push the body to adapt getting fitter and healthier. Also, a class setting tends to be more motivating and attending quickly becomes part of your routine.

The pain of intervals is temporary but if you continue training the benefits last a lifetime.