Exercise with high intensity may sound very challenging, and even scary, for persons diagnosed with diastolic heart failure. As breathlessness is one of the main symptoms and the exercise capacity is often very low,  training with an intensity of 95 % of maximum heart rate (more about the different exercise protocols here) seems like an impossible task.

The fear of causing further damage on the heart than the already existing one is very common, and traditionally, the medical advice for patients with cardiovascular diseases in general has been to calm down and, if exercising takes place, only with moderate intensity.

It is no doubt that pushing oneself very hard during exercise can feel very uncomfortable. However, research has shown that exercise with high intensity (85-95 % of maximum heart rate) represents no greater risk of cardiovascular events (e.g. atrial fibrillation, heart attack, etc.) than exercise with moderate intensity (60-70 % of maximum heart rate).

In 2011, a study by Rognmo and colleagues¹ received lots of attention for remarkable results. The sample consisted of 4846 patients with different CHD diagnoses undergoing rehabilitation. The participants were randomly allocated to either moderate or high intensity exercise groups, and reported the amount of exercise hours. When analyzing data, the researchers found that regardless of intensity, the risk of CV events during exercise is extremely low: One fatal cardiac arrest per 129 456 hours of moderate and one non-fatal cardiac arrest per 23 182 hours of high intensity exercise. 

Due to the well-known benefits of high-intensity exercise on several heart functions found in other studies, this type of exercise is emerging as a standard procedure for patients undergoing rehabilitation on several institutions. Our recommendation to everyone, healthy or sick, is therefore to push oneself a little harder during exercise – it is more beneficial for your heart, but still safe.

_{1 Rognmo Ø et al. Cardiovascular risk of high- versus moderate-intensity aerobic exercise in coronary heart disease patients. Circulation 2012 Sep 18;126(12):1436-40.}