Exercise as Therapy: Part 2

Photo Credit: Stream Train Fitness

In the previous blog, Part 1, (Click Here) I discussed exercise as therapy and explained physical activity vs physical fitness. In this blog, Part 2 I will discuss how physical activity and fitness leads to improved health outcomes.

Recommendation for activity

Science has added to our understanding of the biological mechanisms by which physical activity provided health benefits and the physical activity profile (type, intensity, amount) that is associated with enhanced health and quality of life.1 While there are many physical activity and physical fitness recommendations that exist. ACSM/AHA recommends, that all healthy adults from ages 18 to 65 should participate in moderate aerobic activity five days per week for a minimum of 30 minutes.1 A combination of moderate and vigorous intensity aerobic activity can be performed to meet this recommendation. Moderate-intensity aerobic activity, which is generally equivalent to a brisk walk and noticeably accelerates the heart rate, can be accumulated toward the 30-min minimum by performing bouts each lasting 10 or more minutes. A person can meet the recommendation by walking briskly for 30 min twice during the week and then jogging for 20 on two other days.1

How does physical activity and fitness lead to improved health outcomes?

Well to begin, several biological mechanisms may be responsible for the reduction in the risk of chronic disease and premature death associated with routine physical activity.2 Chronic inflammation, as indicated by elevating circulating levels of inflammatory mediators such as C-reactive proteins, has been shown to be strongly associated with most of the chronic diseases whose prevention has benefited from exercise.2 There is compelling evidence that regular physical activity extends longevity and reduces risk for Coronary Heart Disease (CHD), Cardiovascular Disease (CVD), stroke and colon cancer.4  For instance, routine physical activity has been shown to:

• reduce blood pressure
• improve body composition
• reduce abdominal adiposity
• improve weight control
• enhance lipid profiles
• reduce triglyceride levels
• increase high-density lipoprotein (HDL) cholesterol levels
• decrease low-density lipoprotein (LDL) levels.  

Just as for cardiorespiratory fitness, all of the fitness variables have genetic components but also are influenced by environmental factors. For example, the blood lipid profile has a genetic components, but diet is of great importance as well.4 Exercise therapy can have clinical effects, either by directly affecting the disease pathogenesis by improving dominant symptoms of the underlying disease or by enhancing physical fitness, strength and hence quality of life in patients weakened by disease.3 Individuals who are regularly physically active are less likely than sedentary individuals to develop health problems.4 Rather than encouraging individuals to “become fit”, we should instead recommend and encourage individuals to “increase activity” as we can see activity can improve health outcomes.

References:

1Haskell, W. L., Lee, I-M., Pate, R. R., Powell, K. E., Blair, S. N., Franklin, B. A., Bauman, A. (2007). Physical activity and public health: Updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Circulation, 116(9), 1081-1093. doi: 10.1161/circulation.107.185649

2Warburton, D.E.R., Nicol, C.W., & Bredin, S.S.D. (2006). Health benefits of physical activity: The evidence. CMAJ, 174(6), 800-809. doi:10.1503/cmal.051351

3Pedersen, B.K., & Saltin, B. (2006). Evidence for prescribing exercise as therapy in chronic disease. Scandinavian Journal of Medicine & Science in Sports, (16)S1, 3-63. doi:10.1111/j.1600-0838.2006.00520.x

4Blair, S.N., Cheng, Y., & Holder, S.J. (2001). Is physical activity or physical fitness more important in defining health benefits? Official Journal of the American College of Sports Medicine. S379-399.