Cardiovascular disease (CVD) remains the leading cause of deaths in the U.S. The latest report on heart disease and stroke statistics by the American Heart Association relates 379,559 coronary heart disease- and 129,476 stroke-related deaths occurring in 2010 in the U.S.¹ In an attempt to prevent CVD deaths, the American Heart Association recently published recommendations aimed at cardiovascular health promotion.² This document encourages the general population to meet seven defined ideal cardiovascular health metrics, also called “Life’s Simple 7” (i.e., not smoking; being physically active; having normal blood pressure, blood glucose and total cholesterol levels, and weight; and eating a healthy diet). The Department of Health and Human Services Million Hearts® initiative of “Million Hearts and First Lady Michelle Obama’s Let’s Move! initiative are also examples of the general public’s and federal government’s impetus to decrease CVD mortality by fostering physical activity and cardiovascular health promotion. Increasing physical activity is a fundamental part of this effort both at a clinical and a community level.³ However, barriers to achieving and maintaining optimal physical activity include environmental factors, time commitment, and motivation.

The salutary effects of increasing physical activity and exercise training on the cardiovascular system and on CVD risk factor reduction have been studied extensively in large epidemiological studies. The vast majority of these studies shows a graded increase in cardiovascular benefit and reduced CVD mortality with progressive increments in the amount of exertion.⁴ Nonetheless, the minimum exercise intensity, the exact frequency and duration of exercise sessions needed to achieve cardiovascular health and the mortality benefits from exercise are not very well defined.^5,6 Furthermore, it is unclear whether long-term, high-intensity exercise has a ceiling effect beyond which no further cardiovascular or mortality benefit could be derived. Or even more concerning, are there potential deleterious effects of large volumes of long-term endurance exercise?

Recently, a study demonstrated that as little as 15 minutes per day of brisk walking can provide a 14% all-cause mortality risk reduction with a three- year survival benefit over inactive individuals.⁷ In an issue of JACC, an investigation led by Duck-chul Lee studied 55,137 adults from the Cooper Clinic in Dallas, mean age 44 years, and compared the mortality risk between runners and non-runners.⁸ Investigators found that runners had 30% and 45% lower risk of all-cause and cardiovascular mortality, respectively, and a three-year increase in life expectancy over non-runners during a 15-year follow up. The survival benefit was evident even in participants running as little as 5 to 10 min/day and at speeds as slow as 10 minutes a mile. This investigation confirmed that low volumes of exercise, below current guideline recommendations, can have substantial health benefits, particularly if the individual is a persistent runner. Contrary to previous data, the investigation did not demonstrate additional benefits of running on mortality among those running the most. The mortality benefit was similar between these groups.

The prevalence of physical activity has slightly increased since the late 1980s in the U.S.,⁹ and running has become increasingly popular as evidenced by the number of marathon participants across the nation.¹⁰ Despite this slight increase in physical activity, only one in five U.S. adults meets both the aerobic and the muscle strengthening components of the physical activity guidelines.¹¹ The current guidelines recommend at least 2.5 hours a week of moderate-intensity aerobic activity, such as walking, or an hour and 15 minutes a week of vigorous-intensity aerobic activity, such as jogging, or a combination of both.¹² The current data by Lee and colleagues offer an efficacious option to increase physical activity in individuals who are pressed for time, or individuals who could not realistically aim for higher intensity of exertion.

Implementing physical exercise programs is an effective and inexpensive intervention to prevent all-cause and CVD related deaths. Education and behavioral change leading to mild increases in physical activity has a significant benefit in mortality even at low doses. The results of this investigation may encourage people to realize that even some running is better than none. More research is needed to determine dose response at higher exercise levels and to determine whether or not there are deleterious effects of large amounts of long-term endurance exercise on cardiovascular health.

References:

1. Go AS, Mozaffarian D, Roger VL, et al. Heart disease and stroke statistics—2014 update: a report from the American Heart Association. Circulation 2014;129:e28-e292.
2. Lloyd-Jones DM, Hong Y, Labarthe D, et al. Defining and setting national goals for cardiovascular health promotion and disease prevention. Circulation 2010;121:586-613.
3. Ford ES, Ajani UA, Croft JB, et al. Explaining the decrease in U.S. deaths from coronary disease, 1980–2000. N Engl J Med 2007;356:2388-98.
4. Sattelmair J, Pertman J, Ding EL, et al. Dose response between physical activity and risk of coronary heart disease: a meta-analysis. Circulation 2011;124:789-95.
5. William PT. Reduction in incident stroke risk with vigorous physical activity: evidence from 7.7-year follow-up of the national runners' health study. Stroke 40:1921-3.
6. Mason JE, Manson JE, Greenland P, et al. Walking compared with vigorous exercise for the prevention of cardiovascular events in women. <N Engl J Med 2002;347:716-25.
7. Wen CP, Wai JP, Tsai MK, et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. Lancet 2011;378:1244-53.
8. Lee DC, Pate RR, Lavie CJ, et al. Leisure-time running reduces all-cause and cardiovascular mortality risk. J Am Coll Cardiol 2014;64:472-81.
9. Centers for Disease Control and Prevention (CDC). Prevalence of regular physical activity among adults—United States, 2001 and 2005. MMWR Morb Mortal Wkly Rep 2007;56:1209-12.
10. Hoffman MD, Wegelin JA. The Western States 100-Mile Endurance Run: participation and performance trends. Med Sci Sports Exerc 2009;41:2191-8.
11. Centers for Disease Control and Prevention. Press Release: One in five adults meet overall physical activity guidelines (CDC website). 2013. Available at: http://www.cdc.gov/media/releases/2013/p0502-physical-activity.html. Accessed 7/28/2014.
12. U.S. Department of Health and Human Service. 2008 Physical Activity Guidelines for Americans (HHS website). 2008. Available at: http://health.gov/PAGuidelines. Accessed 7/28/2014.

Keywords: American Heart Association, Cause of Death, Walking, Epidemiologic Studies, Health Promotion, Jogging, Leisure Activities, Life Expectancy, Motivation, Physical Exertion, Risk Factors, Risk Reduction Behavior, Running, Smoking, United States Dept. of Health and Human Services, Blood Glucose, Blood Pressure, Cholesterol

< Back to Listings