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Think Thirty

Humprey, Reed H. P.T., Ph.D., FACSM

doi: 10.1249/01.FIT.0000298456.32685.88

Think Thirty! Spreading the Word About the Benefits of Thirty Minutes of Daily, Moderate to Vigorous Exercise.

Reed H. Humphrey, Ph.D., P.T., FACSM, is professor and chair of the School of Physical Therapy & Rehabilitation Science at the University of Montana. He completed a 4-year term as head of the World Council for Cardiovascular and Pulmonary Rehabilitation in 2004 and is a past president of the American Association of Cardiovascular & Pulmonary Rehabilitation. He is associate editor of ACSM's Resources for Clinical Exercise Physiology and past associate editor of ACSM's Guidelines for Exercise Testing and Prescription, fifth edition. Humphrey completes his term as an associate editor for ACSM's Health and Fitness Journal® with this issue.

In my final column for ACSM's Health and Fitness Journal ®, I have conspired with my colleague Steven Tepper, P.T., Ph.D., and his colleague Mark Baughman P.T., ATC, OCS, to address a simple message that needs to reach a far wider audience; 30 minutes of daily moderate-to-vigorous exercise is the common denominator in solving the current chronic disease crisis in which we are presently engaged. From the surgeon general to the gym floor leader, including every point of contact in between (health-care providers, physical educators, school administrators, and, yes, health insurance providers), a single evidence-based message has to be drummed into the daily routine of every man, woman, and child if we are to be successful in altering the exercise and activity behaviors in America.



The message may seem both redundant and almost too simplistic-surely, everyone has heard this message multiple times-but if we are continuing to lose ground with our clients, it becomes imperative to investigate the delivery.

It is well understood by the readers of this Journal that indeed, there are varying volumes of exercise advocated by different groups, from ACSM to the Institute of Medicine to different agencies within the federal government, and all are based on the weight of scientific evidence in the context of the outcome measure in question: general health, fitness, weight loss (with different levels depending on a goal of prevention or the thresholds necessary to maintain lost weight), and cardioprotection or cardiovascular disease (CVD) mortality. Consumers can be confused by recommendations that range from 30 to 60 minutes to even 90 minutes! Indeed, there are compelling reasons to do 60 or upward of 90 minutes of daily activity, but that depends on the desired outcome. At the core of any program should be a 30-minute (or three 10-minute bouts) commitment to improving health and fitness given the wealth of science that supports this threshold of exercise done on most days of the week.



We propose that you adopt this message and advocate it in your place of work, in your community, and among your health-care colleagues. We believe that if we convince all those able to just walk briskly 30 minutes each day, health care, as we know it, would radically change in this country!


  • Reduce the risk of CVD and atherosclerosis. If everyone walked for 30 minutes daily at 3 to 4 mph, it would decrease the number of CVD deaths per year by 30% (284,886 deaths/year) (1-4).
  • Reduce the risk of type diabetes by 58% in persons at high risk (5).
  • Reduce risk of stroke by 24% by walking more than 3 mph for 2.5 hours per week as compared with nonexercisers. Walk more than 3 mph for 5 hours per week, and lower risk of stroke by 46% compared with nonexercisers (6,7).
  • Reduce risk of breast cancer by 20%in white and African American women who regularly exercise compared with inactive females (8,9).
  • Reduce risk of mortality with patients who have been diagnosed with breast cancer by 25% compared with sedentary individuals. Further reduce risk by 50% if walking 3 to 8 hours per week.
  • Reduce resting blood pressure (10,11).
  • Reduce the risk of pancreatic cancer among overweight individuals.
  • Reduce risk of osteoporosis and improve bone health.
  • Reduce risk of cholecystectomy (gallbladder removal) in women by 31% (12).
  • Reduce risk of depression among elderly adults. In elderly adults classified with major depressive disorder,a 50% reduction of the disorder occurred after just 4 months of exercise (13,14). Improved overall aerobic fitness and functional capacity.
  • Daily walking of 30 minutes for 12 weeks has been shown to lower overall body weight and decrease percent body fat (15-17).

Thirty minutes of moderate-to-vigorous exercise will not likely yield optimal outcomes for those who are overweight or trying to prevent weight regain, and there may be compelling reasons to advocate for progressively increasing exercise volume once clients are behaviorally engaged and consistently meeting the 30-minute threshold. For those needing an hour or more to achieve their specific outcomes, advocating multiples of 30 minutes-two (60 minutes) or three (90 minutes) "units" distributed as needed through the days and week-is a logical and easy translation for consumers when consistently applied by health and fitness professionals.

Think thirty, and thanks for changing the lives of your clients.

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ACSM's Fitness Book, Third Edition-Helps clients keep overall personal fitness on track with a proven step-by-step program from the experts. (ISBN: 0-7360-4406-X)

ACSM offers a seven-book Action Plan for Health series that provides exercise and nutrition plans for special populations:

  • ACSM's Action Plan for Allergies (ISBN 0-7360-6279-3)
  • ACSM's Action Plan for Arthritis (ISBN 0-7360-4651-8)
  • ACSM's Action Plan for Diabetes (ISBN 0-7360-5459-6)
  • ACSM's Action Plan for High Blood Pressure (ISBN 0-7360-5140-6)
  • ACSM's Action Plan for High Cholesterol (ISBN 0-7360-5440-5)
  • ACSM's Action Plan for Menopause (ISBN 0-7360-5618-1)
  • ACSM's Action Plan for Osteoporosis (ISBN 0-7360-5482-0)

To order any of these titles, visit and click on "News," then "Books and Other Media."

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1. Pate, R., M. Pratt, N. Blair, et al. Physical activity and public health. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. The Journal of the American Medical Association 273(5):402-407, 1995.
2. Wei, M., J.B. Kampert, C.E. Barlow, et al. Relationship between low cardiorespiratory fitness and mortality in normal-weight, overweight, and obese men. The Journal of the American Medical Association 282(16):1547-1553, 1999.
3. Manson, J.E., F. Hu, J. Rich-Edwards, et al. A prospective study of walking as compared with vigorous exercise in the prevention of coronary heart disease in women. New England Journal of Medicine 341(9):650-658, 1999.
4. Tully, M., W. Cupples, K. Chan, et al. Brisk walking, fitness, and cardiovascular risk: a randomized controlled trial in primary care. Preventive Medicine 41:622-628, 2005.
5. Knowler, W.C., E. Barrett-Connor, S.E. Fowler, et al. Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or meformin. New England Journal of Medicine 346(6):393-403, 2002.
6. Hu, F., M. Stampfer, G. Colditz, et al. Physical activity and risk of stroke in women. The Journal of the American Medical Association 283(22):2961-2967, 2000.
7. Lee, I., C. Hennekens, K. Berger, et al. Exercise and risk of stroke in male physicians. Stroke 30(1):1-6, 1999.
8. Thune, I., T. Brenn, E. Lund, et al. Physical activity and the risk of breast cancer. New England Journal of Medicine 336(18):1269-1275, 1997.
9. Bernstein, L., A. Patel, G. Ursin, et al. Lifetime recreational exercise activity and breast cancer risk among black women and white women. Journal of National Cancer Institute 97(22):1671-1679, 2005.
10. Pescatello, L.S., B.A. Franklin, R. Fagard, et al. American College of Sports Medicine. American College of Sports Medicine position stand. Exercise and hypertension. Medicine & Science in Sports & Exercise ® 36(3):533-553, 2004.
11. Roberts, C., D. Nosratola, R. Vaziri, et al. Effect of diet and exercise intervention on blood pressure, insulin, oxidative stress, and nitric oxide availability. Circulation 106:2530, 2002.
12. Leitzmann, M., E. Rimm, W. Willett, et al. Recreational physical activity and the risk of cholecystectomy in women. New England Journal of Medicine 341(11):777-784, 1999.
13. Strawbridge, W., S. Deleger, R. Roberts. Physical activity reduces the risk of subsequent depression for older adults. American Journal of Epidemiology 156(4):328-334, 2002.
14. Babyak, M., J. Blumenthal, S. Herman, et al. Exercise treatment for major depression: maintenance of therapeutic benefit at 10 months. Psychosomatic Medicine 62:633-638, 2000.
15. Ignarro, L.J., M.L. Balestrieri, C. Napoli. Nutrition, physical activity, and cardiovascular disease: an update. Cardiovascular Research 73(2):326-340, 2006.
16. Bond, B., A. Perry, L. Parker, et al. Dose-response effect of walking exercise on weight loss. How much is enough? International Journal of Obesity and Related Metabolic Disorders 26(11):1484-1493, 2002.
17. Sanders, L.F., G.E. Duncan. Population-based reference standards for cardiovascular fitness among U.S. adults: NHANES 1999-2000 and 2001-2002 Medicine & Science in Sports & Exercise ® 38(4):701-707, 2006.
© 2007 American College of Sports Medicine