Minimal amount of exercise to prolong life: To walk, to run or to wogging?
Chi Pang Wen, M.D, Dr.PH.1, 2 Jackson Pui Man Wai, Ph.D.3 Min Kuang Tsai, MS.1 Chien Hua Chen, M.D, MPH.4-5
1. Institutes of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan 2. China Medical University Hospital, Taichung, Taiwan
3. Institute of Sport Science, National Taiwan Sport University, Taoyuan, Taiwan 4. Digestive Disease Center, Show-Chwan Memorial Hospital, Changhua, Taiwan 5. Hungkuang University, Taichung, Taiwan
Brief title: To walk or to run to prolong life in minimal amount Corresponding author: Chi-Pang Wen
Institute of Population Health Sciences, National Health Research Institutes
Address: National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan
E-mail: cwengood@nhri.org.tw Phone: +886-37-246-166*36318 Fax: +886-37-586-261
Conflicts of interest
All authors declare that we have no conflicts of interest. Acknowledgements
This study is supported in part by Taiwan Department of Health Clinical Trial and Research Center of Excellence (DOH102-TD-B-111-004).
soul and physical activity for the body. Lack of activity destroys human beings, and exercise can save human beings. Plato 400 B.C.
For man to assume great responsibility, God tested his mental commitment, labored his muscles and bones, and starved his body. Mencius 300 B.C.
Exercise is perceived more as a nice habit to have, and not necessarily an essential part of life. Most of us agree with the notion that physical activity is beneficial, but a large proportion of the global population remains
sedentary, ranging from 40% to 80%. Surveys in the US (1) and the UK (2) showed that more than half of all adults failed to comply with the 2008
Physical Activity Guidelines for the Americans (3), recommending 30 minutes a day of moderate intensity or 75 minutes a week of vigorous intensity. The situation is worse in Asian countries where up to 80% do not meet the
guidelines (4). Affluence has led to less manual labor and more use of motor vehicles for transportation. Although such low compliance with physical activity guidelines could be due to unawareness of the strong benefits of exercise, it is also possible that setting a standard perceived as being too high could deter many people from even trying. Instead, setting up goals that could be attained with minimal amount of effort becomes important.
In this issue of JACC, Duck-chul Lee et al found minimal running of 5-10 minutes per day is associated with reduced mortality from all-cause (30%) or from cardiovascular diseases (45%), and could add 3 years of life expectancy from a 15-year follow up of 55,137 adults at the Cooper Clinic in Dallas, Texas. This study found that running, even less than the recommended amount of time or slower speeds, was associated with significant benefits. This minimal amount, half the
reported in the Lancet in 2011 by Wen et al (4), half the current recommended 150 minutes a week or 30 minutes a day. Both showed a 3-year extension of life and both are good news to the sedentary, as finding 5-15 minutes a day is several times easier than finding 30 minutes to exercise. While any amount of exercise is better than none and small amount of exercise could work wonders, prior to these two studies, no conclusive timeline has been identified with sufficient statistical power to show definitive health benefits (4).
Runners, recruited from the Aerobic Center, were usually more motivated and had less risk factors like smoking or obesity. They are usually healthier to start with. In contrast, non-runners had more co-morbidities such as diabetes or hypertension. Like most observational studies, the causality of the study conclusion is not straight forward to establish. However, Lee’s results are entirely consistent with findings from prospective randomized trials in
secondary cardiovascular prevention that show a clear mortality benefit from regular exercise (5). In this study, authors used statistical methods to control confounders and also did sensitivity analysis looking into different groups of people and found the results consistent. As such, the direct health benefits of exercise are irrefutable. The reality is that a virtuous cycle exists for an
iterative process of incremental exercise promoting incremental health, and the healthier individuals in turn being more likely to exercise, blurring the simple cause and effect relationship.
Many studies showed that higher intensity exercise yielded more
favorable effects on mortality and disease risks than that of the lower intensity exercise (6-8). The benefits of running were superior to walking not only at iso-volume, or similar amount of exercise, but also at smaller volume than
walking (4). Running beats walking hands down by a factor of 2 – 4 to 1, in terms of mortality reduction at iso-volume. As shown in the Figure, a 5-minute run is as good as 15-minute walk, and a 25-minute run can generate benefits that would take walking four times longer to accomplish. As the authors indicate, for younger individuals who are pressed for time, running is a far better option for time efficiency.
The huge advantages of running, however, come with a hefty cost to the body and to the habit formation. To the body, persistent running is invariably associated with injuries (9), even among leisure-time runners. One such study reported one out of 4 (25.9%) experienced injuries that were significant
enough to restrict running in an 8-week practice run for 4 miles (10). Even experienced runners with good preparation could not avoid injuries. However, for the suggested minimal running like 5-10 minutes per day, injuries could be minimized or sharply curtailed. For the habit formation, running requires a much bigger commitment than walking. For the beginners, running can be painful, and laborious and difficult to sustain. Authors in this study suggested a “progressive transitional phase” by the inactive to start from walking before running. It is obvious that the aforementioned health benefits cannot be achieved when an injured individual had to quit running. On the other hand, the concern for sudden death from running is so miniscule that the risk could be ignored, reported as 4 per million (11), when compared with an average coronary heart risk of 20%-30% in the lifetime of an inactive individual.
“To walk or to run, that is the question”.
social networking. It does not require shower facility that running requires. The most important advantage of walking, however, is its high safety factor that can be sustained for months and for years. Our exercise recommendation
prior to the 1990s was rooted in the "athletic" paradigm and stressed vigorous activity. After that, the fitness-target approach was augmented by a more inclusive population-based health-target approach, which gave credence to the benefits of moderate-intensity activity or walking (12). The choice between walking and running is simple if identical health benefits can be similarly achieved and easier to sustain, particularly for the majority of the population who are sedentary. Alternatively, as the word “wogging” was coined from walking mixed with jogging, wogging could be recommended for those who found walking too time consuming.
Doctors are faced with a similar dilemma to counsel apparently “healthy patients” as to how to exercise. Patients expect an “exercise prescription” from the doctors. The term exercise prescription sounds too complicated for us to provide customized recommendations for each of our patients. In fact, 15 minutes of brisk walking or 5 minutes of running is all it takes for most clinic patients. Exercise is medicine and is a miracle drug. The list of diseases that exercise can prevent or delay onset, modify progression or improve outcome is longer than we currently realize. It helps both the body and the soul. It works on every part of our body system. The study by Lee et al showed a whopping reduction of 45% of
cardiovascular disease from 5-10 minute running. Even 15-minute of brisk walking reduced 25% mortality from ischemic heart disease (4). Alternatively, stress the harms of inactivity to promote exercise (13). Tell patients that inactivity can lead to a 25% increase in heart disease, and a 45% increase in cardiovascular disease
mortality, not to mention a 10% increase in cancer and diabetes (4) and untold mental depression. While most patients are aware of the benefits of exercise, it is up to us to move them from wishful thinking to practical reality, and move them from the contemplation phase to the action phase (14). Patients are smart and tend to judge our sincerity by our body language. Even with one-minute counseling, it is our attitude and our commitment toward emphasizing the importance of exercise or the harms of inactivity that would move patients. The simple message, delivered with sincerity, needs to be repeated every time we encounter our patient.
We doctors not only should “walk the talk”, spending at least 15 minutes a day in dedicated exercise, but also become advocates for building physical activity culture in our society. We do not need to be an athlete to exercise. It should be part of our daily routine. Make the 15-minute walk or 5-minute run part of the clinic advice and revise the current “physical activity
recommendation for the Americans”, for helping our patients in particular and for helping our society as a whole.
Figure legend:
Figure: Comparison of mortality benefits between running and walking by exercise time. (Data from reference 4)
