Carl J. Lavie, M.D., FACC, Richard V. Milani, M.D., FACC, Thomas J. Lavie, M.D.

We read with interest the excellent paper by Kokkinos and Myers¹ on the importance of exercise training (ET) and cardiorespiratory fitness (CRF) for cardiovascular (CV) health. They quoted Hippocrates regarding the benefits of physical activity and ET. Likewise, we are reminded that Cicero also noted centuries ago that “it is exercise alone that supports the spirit, and keeps the mind in vigor.” The paper by Kokkinos and Myers, however, fails to acknowledge the impressive evidence regarding the impact of physical activity, ET, and CRF on psychological risk factors that independently adversely affect CV prognosis.

Despite considerable evidence supporting the importance of psychological risk factors in CV diseases, this has not been emphasized in general medicine or by CV disease specialists. Although much research has focused on the role of depression as a CV risk factor that also adversely affects recovery following major CV events, several recent studies have also reported on anxiety and hostility as major risk factors for CV events. In fact, the INTERHEART study² reported that psychosocial stress (PSS) accounts for nearly one-third of the population’s attributable risk of developing acute myocardial infarction, placing it behind only lipids and smoking in importance among the modifiable coronary risk factors. Although pharmacologic therapy has been the standard approach to improving symptoms of PSS, these medications may help symptoms but have not been shown to favorably alter prognosis of patients with CV diseases.

On the other hand, ET has been associated with reductions in PSS and its related mortality. In fact, in a study of 635 consecutive coronary patients, we demonstrated a very high prevalence of PSS, with > 50% to 80% reductions in the prevalence of anxiety, hostility, and depression following formal cardiac rehabilitation and ET training (CRET).³ Moreover, we demonstrated that persistent depression following coronary events is associated with three-fold increase in three-year mortality.⁴ However, coronary patients with depression who participated in formal CRET programs had 70% reductions in three-year mortality compared with control depressed patients. Additionally, we demonstrated that patients with significant improvements in CRF had improvements in both depression and depression-related mortality. In a more recent study of 522 coronary patients, we demonstrated that a composite score for PSS (including evaluations of depression, anxiety, and hostility) was a powerful predictor of three-year mortality.⁵ Following CRET, very high mortality was noted only in patients with high PSS who did not significantly improve peak oxygen consumption (a precise measure of CRF), whereas groups with either low PSS or high PSS who significantly improved CRF with CRET had low mortality. Our data, therefore, suggest that most of the benefit from CRET was explained by improving CRF in the subgroup of patients with high PSS.

Although we congratulate Kokkinos and Myers for their excellent review, we also should emphasize the importance of PSS in CV diseases and the potential for ET and improvements in CRF to impact PSS and stress-related increased mortality.

References

1. Kokkinos P, Myers J. Exercise and physical activity: clinical outcomes and applications. Circulation 2010;122:1637-1648.
2. Rosengren A, Hawken S, Ounpuu S, Sliwa K, Zubaid M, Almahmeed WA, Blackett KN, Sitthi-amorn C, Sato H, Yusuf S; INTERHEART investigators. Association of psychosocial risk factors with risk of acute myocardial infarction in 11119 cases and 13648 controls from 52 countries (the INTERHEART study): case-control study. Lancet 2004;364:953-962.
3. Lavie CJ, Milani RV. Adverse psychological and coronary risk profiles in young patients with coronary artery disease and benefits of formal cardiac rehabilitation. Arch Intern Med 2006;166:1878-1883.
4. Milani RV, Lavie CJ. Impact of cardiac rehabilitation on depression and its associated mortality. Am J Med 2007;120:799-806.
5. Milani RV, Lavie CJ. Reducing psychosocial stress: a novel mechanism of improving survival from exercise training. Am J Med 2009;122;931-938.