by MEGHAN BOTHWELL, BS, MS, CSCS

In 2016 the American Heart Association (AHA) put forth a compelling case for exercise as a vital sign⁸ – this will be the 7^th vital sign – in addition to the 6 others already on the list: control cholesterol, eat healthy, lose weight (BMI), manage BP, smoking status, reduce blood sugar (fasting glucose levels).

Cardiovascular Disease: A major public health problem

While success has been achieved in improving these highly modifiable vital signs over the last decade, physical activity remains largely unchanged or worsened.⁴ Cardiovascular disease has remained the leading cause of morbidity & mortality in industrialized nations for more than half a century.²  A recent National Health and Nutrition Examination Surveys (NHANES) revealed that 64% of the population exhibit either inadequate or intermediate physical activity participation; second only to a strong tend to embrace unhealthy diets.⁴

Cardiorespiratory Fitness and disease-specific mortality (specifically cancer)

Numerous epidemiological studies have further illuminated the impact of CRF on mortality^1-10 — longer follow-up periods, examining individuals throughout the lifespan, diversifying subject populations by age, sex, ethnicity, and specific medical histories, and by incorporating changes in CRF in the overall risk assessment.

Historically, studies have emphasized CRF as a strong predictor of all-cause and CVD mortality, however recent work has examined the relationship between CRF and disease-specific mortality – specifically cancer.  Low CRF has been associated with an increased risk of cancer, while unfortunately the relationship with cancer mortality being less studied.²

Exercise has been known to have a positive impact for patients undergoing cancer treatment by helping to mitigate side effects from therapy.  However, little is known regarding the effects of an acute bout or prolonged-training program of exercise on cancer tumor physiology.  Wiggins et al.¹² found that aerobic exercise, specifically moderate-intensity exercise, can have the potential to improve an “anti-tumor”

environment – improving tumor perfusion & drug delivery, and engaging in an antitumor systemic immune response (providing a protective effect against infections). Nevertheless, high CRF has been reportedly been linked w/ lower cancer mortality in male Japanese¹¹, Korean⁶, and Norwegian⁹ cohorts. Similarly, Jensen et al.⁵ reported an inverse graded relationship between CRF and cancer mortality in Danish men followed for 42 years.  Importantly, the relationship persisted after excluding men who died in the first 20 years of the follow-up, minimizing the influence of reverse causation.

Conclusion

The recently published AHA Scientific Statement makes a compelling case for routinely assessing CRF and making it a clinical vital sign.  Certainly, the plethora of overwhelming research strongly supports the assessing CRF and its importance as an independent predictor of all-cause and disease-specific mortality in varied populations.

References

1. Blair SN, Kohl HW, Paffenbarger RS, Clark DG, Cooper KH, Gibbons LW. Physical Fitness and All-Cause Mortality: A Prospective Study of Healthy Men and Women. 1989;262(17):2395–2401. doi:10.1001/jama.1989.03430170057028
2. Harber, M., Kaminsky, L., Arena, R., Blair, S., et al. Impact of Cardiorespiratory fitness on All-cause and Disease-Specific Mortality: Advances since 2009. Progress in Cardiovascular Diseases. 2017; 60 (11-20). doi:10.1016/j.pcad.2017.03.001
3. Huffman, M., Capewell, S., Ning, H., Shay., C., et al. Cardiovascular health behavior and health factor changes (1988-2008) and projections to 2020: results from the National Health and Nutrition Examinations Surveys. Circulation. 2012; 125(21):2595-602.
   doi: 10.1161/CIRCULATIONAHA.111.070722/-/DC1.
4. Jensen, M., Holternmann, A., Bay, H., Gyntelberg, F., et al. Cardiorespiratory fitness and death from cancer: a 42-year follow-up from the Copenhagen male study. Br J Sports Med.
5. Kodama S, Saito K, Tanaka S, Maki M, Yachi Y, Asumi M, Sugawara A, Totsuka K, Shimano H, Ohashi Y, Yamada N, Sone H. Cardiorespiratory Fitness as a Quantitative Predictor of All-Cause Mortality and Cardiovascular Events in Healthy Men and Women A Meta-analysis. 2009;301(19):2024–2035. doi:10.1001/jama.2009.681
6. Park, M., Chung., S., Chang, Y, & Kim, K. Physical Activity and physical fitness as predictors of all-cause mortality in Korean men. Korean Med Sci. 2009; 24:13-19.
7. Pilkerton, CS., Singh, S., Bias, T., Frisbee, S. Changes in cardiovascular health in the United States, 2003-2011. 2015; 4(9):e001650.
8. Quindry, J., Franklin, B. Cardioprotective Exercise and Pharmacologic Interventions as Complementary Antidotes to Cardiovascular disease. Exercise and Sport Sciences Review. 2017; 46(1):5-17. doi:10.1249/JES.0000000000000134.
9. Robsahm, T., Falk, R., Heir, T., et al. Measured cardiorespiratory fitness and self-reported physical activity: associations with cancer risk and death in a long-term prospective cohort study. Cancer Med. 2016;5:2136-2144.