Exercise Intensity, Not Quantity Reduces Risk of Death from Heart Disease

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New research suggests that the intensity of exercise might be more important than the quantity in helping to prevent death from heart disease and other causes.

In a study presented last week at the European Society of Cardiology Congress 2011, scientists described new research that examined the relationship between exercise duration, exercise intensity, and total risk of death [1]. Lead researcher Peter Schnohr of Copenhagen, Denmark explained that both male and female cyclists had a decreased total risk of death if they cycled vigorously (by their own perception), but that cycling duration didn’t show a similar protective effect.

Cycling vigorously

Schnohr found that male cyclists who rode at an intense level of effort lived, on average, 5.3 years longer than those who cycled slowly. Men who cycled at moderate intensity lived an average of 2.9 years longer than the leisurely cyclists. For women, vigorous and moderate cyclists lived 3.9 and 2.2 years longer, respectively, than those who rode at a slow pace.

While vigorous cycling was correlated with a reduced risk of death from all causes, the correlation between vigorous cycling and reduced risk of death from coronary heart disease was particularly strong. Across all ages and genders and adjusted to account for differences in activities, risk factors, and behaviors such as smoking, people who rode vigorously for 30 minutes per day had only 18% the risk of dying from coronary heart disease as compared to those who rode slowly.

Coronary heart disease is the leading cause of death for both men and women in the United States [2], and inactivity is a major heart disease risk factor. Currently, the American Heart Association recommends plenty of exercise — at least 150 minutes per week — to decrease risk of coronary heart disease [3].

Coronary Heart Disease: Narrowing of the small vessels that supply oxygenated blood to the heart muscle due to buildup of plaque — a substance consisting of cholesterol and other fatty substances — on the inside walls of the vessels. This causes reduced blood flow to the heart muscle, which can lead to heart attack.

There are several reasons exercise is though to be so protective against coronary heart disease. People who exercise regularly are less likely to be overweight and have high blood pressure, both of which are risk factors for heart disease. Additionally, exercise can also help improve cholesterol levels, decreasing LDL and increasing HDL.

LDL: Low-density lipoprotein, commonly called “bad” cholesterol. LDL contributes to buildup of plaque inside artery walls. Consuming saturated fat, which comes primarily from animals, and trans fat — found in processed foods — increases your LDL level.
HDL: High-density lipoprotein, commonly called “good” cholesterol. HDL helps your body rid itself of excess cholesterol by carrying cholesterol in the blood and in arterial plaque to the liver, which excretes it.

Schnohr’s latest study strengthens the correlation between exercise intensity and reduced risk of death that he and colleagues first reported in 2007 [4]. The earlier study found that vigorous walking decreased risk of death from all causes more than average-effort walking, which nevertheless showed a protective effect as compared to slow walking.

Despite the emphasis on exercise duration by the American Heart Association, Schnohr was unable to correlate exercise duration with risk of death in either study. Based upon his findings, Schnohr suggests it’s healthiest to find time to exercise vigorously for at least 30 minutes every day of the week.


  1. Cycling fast: vigorous daily exercise recommended for a longer life. European Society of Cardiology press release. 2011 Aug 29.
  2. Heron et al. Deaths: Final data for 2006. National Vital Statistics Reports. 2009 Apr;57(14).
  3. American Heart Association Guidelines. Accessed 2011 Sep 4.
  4. Schnohr et al. Intensity versus duration of walking: Impact on mortality: the Copenhagen City Heart Study. Eur J Cardiovasc Prev Rehabil 2007;14:72-78.
    View abstract
About the Author

Kirstin Hendrickson, Ph.D., is a science journalist and faculty in the Department of Chemistry and Biochemistry at Arizona State University. She has a PhD in Chemistry, and studied mechanisms of damage to DNA during her graduate career. Kirstin also holds degrees in Zoology and Psychology. Currently, both in her teaching and in her writing, she’s interested in methods of communicating about science, and in the reciprocal relationship between science and society. She has written a textbook called Chemistry In The World, which focuses on the ways in which chemistry affects everyday life, and the ways in which humans affect each other and the environment through chemistry.