Improving Cardiovascular Fitness-5 to 10 minutes at a Time

By Glenn A. Gaesser, Ph.D.

Physical inactivity is one of the most significant health problems in America, ranking as one of the leading contributing causes of premature death among US adults¹.  Only about one in five Americans exercises enough to achieve health and fitness benefits.  Yet most Americans probably "know" they should exercise more than they do.  So why do roughly 80 percent of us remain too sedentary?   "Time," or rather the lack of it.  Indeed one of the most frequently mentioned reasons for not exercising is perceived lack of time^1,2.  Most sedentary Americans insist they just don't have time to devote to fitness.

But it's not as if Americans have been told they need to exercise like marathon runners to become fit.  For the past couple of decades the dominant fitness prescription for improving cardiovascular health requires about the same amount of time as watching a few TV shows per week: 20 to 60 minutes of continuous effort, three to five days per week, at an intensity sufficient to elevate heart to at least 60 percent of maximum³.  Accordingly, just three 20-to-30-minute sessions per week at an intensity equivalent to that of brisk walking is sufficient for most men and women to develop and maintain a cardiorespiratory fitness level that reduces morbidity and mortality rates¹.

The problem with this fitness formula, however, is that few Americans of any age have embraced it.  They may well rationalize, for example, that a 30-minute exercise session takes two or three times as long to actually perform-driving to and from a fitness club, changing, showering, etc.  Perceived lack of time.

Some encouraging news, though, comes from some exciting research that shows that multiple, short-bouts of exercise (typically brisk walking), as short as five minutes, spread out over the course of the day, can significantly improve cardiovascular health and assist with weight loss and weight-loss maintenance^4-15.

The multiple short-bout approach to fitness may have considerable appeal for time-constrained individuals who have busy schedules, but with enough flexibility to get in a few 5-to-10-minute brisk walks on most days of the week.

Benefits of Short Bouts of Brisk Walking

In one study 47 women were assigned to either a control group or one of two exercise groups: one 30-minute session or three 10-minute sessions⁵.  Both groups walked at about 75% of maximum heart rate five days/week for 10 weeks.  Improvements in cardiovascular fitness were a very healthy 8 to 9 % for both exercise groups.  Interestingly, decreases in body weight and waist measurement were greater for the short-bout group.  The authors concluded that:

"Repeated short bouts of brisk walking, a pattern easily incorporated into daily living, can improve physical fitness and help with weight regulation in women exposed to the health hazards of a sedentary lifestyle."

Another study⁶ compared not just a 1 x 30-minute group and a 3 x 10-minute group, but added a third group: 30 minutes of exercise per day in any combination of bouts as long as each bout was at least 5 minutes.  Each group performed brisk walking, starting at 3 days/week and progressing to 6 days/week, for 16 weeks.   All groups improved cardiovascular fitness levels and reduced systolic blood pressure by the same amount.

A unique feature of this second study was that the researchers assessed adherence to the program during a 16-week period immediately following the initial 16-week intervention.  At 32 weeks all groups had similar increases in cardiovascular fitness and similar decreases in blood pressures and body fat.  These findings suggest that 30 minutes of walking on most days of the week, with sessions lasting as little as 5 minutes at a time, can improve cardiovascular health and body composition in previously sedentary adults.- Brisk Walks of Just 5 to 6 Minutes Are Enough

A more recent study⁷ confirmed the benefits of very short (5-6 minutes) exercise bouts for improving health and fitness.  In this study of 50 individuals ages 35 to 60, cardiovascular fitness was improved similarly in those who performed 30-minute exercise routines or performed the same amount of exercise but with the majority of exercise bouts lasting 6 minutes or less.   Because the exercise was light-to-moderate, such as brisk walking, it did not require special clothing or equipment, and could be easily incorporated into daily routines.  Who can't spare 5 or 6 minutes several times per day for a brisk walk?

Multiple Short Walks Are Also Good For Weight Control

The "multiple short-bout approach" to fitness may also work well for those interested in weight control.  Researchers at the University of Pittsburgh have published several reports demonstrating the efficacy of this approach in women^10-12.  In one, 56 sedentary obese women were examined during a 20-week intervention that involved exercise and reduced-fat diet¹⁰.  Whether the women walked 30-40 minutes at one time, or performed three to four 10-walks during the day made no difference-both groups lost equal amounts of weight (about 20 pounds during the 20-week study). 

In a subsequent study¹¹ this same research group looked at how much exercise it took to maintain the weight loss achieved by diet and exercise.  A formal diet and exercise program for 6 months preceded 12 months of unsupervised follow-up.  Women who accumulated less than 150 minutes of brisk walking per week lost only 15 pounds at 6 months and regained half of that by 18 months.  Women who accumulated between 150 and 200 minutes of walking per week lost 23 pounds in 6 months and regained only about 4 pounds at 18 months.  By contrast, women who exercised the most--at least 200 minutes per week--lost nearly 28 pounds at 6 months and regained no weight over the last 12 months of the study.  It did not matter if the women got in all their walking in one session, or spread it out in shorter, 5-to-10-minute walks over the course of the day, what mattered most was the total time spent walking per week-and ~200 minutes seemed to be key.

Two hundred minutes per week averages out to 28.5 minutes per day, and might be achieved in one session or in several brisk walks in the 5-to-10 minute range.  Both strategies appear to be equally effective.

An Attractive-and Doable--Alternative

Accumulating several short walks of 5-to-10 minutes may be an attractive option for the millions of Americans who feel they cannot set aside bigger chunks of time to exercise.  Another plus is that brisk walking appears to be a suitable mode of exercise to achieve significant gains in cardiovascular fitness.  This may have a very positive public health impact: obese individuals who achieve just a moderate level of cardiovascular fitness (a level that can be achieved by accumulating ~30 minutes per day of brisk walking on most days of the week) can greatly reduce their risk of premature death, even while remaining clinically obese¹⁶.

The road to a fitter and healthier body is wide enough for everyone.  I encourage you to walk it, even if only five minutes at a time.

1. Physical Activity and Health: A Report of the Surgeon General.  Atlanta: US Departments of Health and Human Services, Centers for Disease Control and Prevention, 1996.
2. Anderson RE, et al.  Encouraging patients to become more physically active: The physician's role. Ann Int Med 1997; 127: 395-400.
3. ACSM Position Stand on The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness and Flexibility in Healthy Adults.  Med Sci Sports Exerc 1998; 30: 975-991.
4. Hardman AE.  Accumulation of physical activity for health gains: what is the evidence?  Br J Sports Med. 1999; 33: 87-92.
5. Murphy MH, Hardman SE.  Training effects of short and long bouts of brisk walking in sedentary women.  Med Sci Sports Exerc 1998; 30: 152-157.
6. Coleman KJ, Raynor HR, Mueller DM, et al.  Providing sedentary adults with choices for meeting their walking goals.  Prev Med 1999; 28: 510-519.
7. Macfarlane DJ, Taylor LH, Cuddihy TF.  Very short intermittent vs continuous bouts of activity in sedentary adults.  Prev Med 2006; 43: 332-336.
8. Boreham CAG, Wallace WFM, Nevill A.  Training effects of accumulated daily stair-climbing exercise in previously sedentary young women. Prev Med 2000; 30: 277-281.
9. Jakicic JM, Wing RR, Butler BA, Robertson RJ.  Prescribing exercise in multiple short bouts versus one continuous bout: effects on adherence, cardiorespiratory fitness, and weight loss in overweight women. Int J Obes 1995; 19: 893-901.
10. Jakicic JM, Winters C, Lang W, Wing RR.  Effects of intermittent exercise and use of home exercise equipment on adherence, weight loss, and fitness in overweight women.  JAMA 1999; 282: 1554-1560.
11. Snyder KA, Donnelly JE, Jacobsen DJ, et al.  The effects of long-term, moderate intensity, intermittent exercise on aerobic capacity, body composition, blood lipids, insulin and glucose in overweight females. Int J Obes 1997; 21: 1180-1189.
12. Donnelly JE, Jacobsen DJ, Snyder Heelan K, et al.  The effects of 18 months of intermittent vs continuous exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females.  Int J Obes 2000; 24: 566-572.
13. Lee I-M, Sesso HD, Paffenbarger RS.  Physical activity and coronary heart disease risk in men: Does the duration of exercise episodes predict risk?  Circulation 2000; 102: 981-986.
14. DeBusk RF, Stenestrand U, Sheehan M, Haskell WL.  Training effects of long versus short bouts of exercise in healthy subjects. Am J Cardiol 1990; 65: 1010-1013.
15. Ebisu T.  Splitting the distance of endurance running: on cardiovascular endurance and blood lipids. Jpn J Phys Educ 1985; 30: 37-43.
16. Lee CD, Blair SN, Jackson AS.  Cardiorespiratory fitness, body composition, and all-cause and cardiovascular disease mortality in men.  Am J Clin Nutr 1999; 69: 373-380.