Last Updated:  04/19/2009

The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author.  Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.

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EXERCISE IN MIDDLE AGE & RISK OF DEATH

We all know that getting regular exercise is an important part of staying healthy.  Low levels of physical activity have been directly linked to a higher risk of cardiovascular disease and cancer, which are the two most common causes of death throughout most of the world.  We also know that even moderate levels of increased physical activity can improve overall health and reduce the risk of developing life-threatening diseases, while higher levels of regular exercise provide even greater protection against illness and premature death.  Ideally, we should all engage in regular and vigorous physical exercise throughout our entire lives, beginning in childhood and continuing into the latter years of our lives.  If you’ve already reached middle age, however, and you haven’t exactly been a regular at your local neighborhood gym, what clinical or scientific evidence is there that starting a new exercise regimen can substantially improve your prospects of living a longer and healthier life when compared to your more fit same-age peers?  A new prospective long-term clinical research study, performed in Sweden and just published in the British Medical Journal, includes some very important data that will, hopefully, provide sedentary middle-aged folks with an even greater incentive to slip on some exercise togs, and hit the gym or track right away.

In this prospective cohort study, 2,205 men, all of whom were 50 years old when they entered the study between 1970 and 1973, were followed for an average of more than 35 years.  All of these participating men were re-evaluated at ages 60, 70, 77, and 82 years of age.  These men were divided into distinct groups, based upon their self-reported levels of physical activity at the time they entered into this research study, and at each point of re-evaluation.  In order to accurately categorize these men in terms of their average levels of physical activity, a previously validated questionnaire was utilized.  The men who answered “yes” to the following question were placed in the “low activity” group: “Do you spend most of your time reading, watching TV, going to the cinema, or engaging in other mostly sedentary activities?”  The men who answered “yes” to the following question (and “no” to the other three questions) were placed in the “medium activity” group: “Do you often go walking or cycling for pleasure?”  Finally, men who answered “yes” to the following two questions were placed in the “high activity” group: “Do you engage in any active recreational sports or heavy gardening at least 3 hours every week” and “Do you regularly engage in hard physical training or competitive sport?”

The annual death rates for this cohort of middle-aged men were then observed for nearly 4 decades, and their risk of death as a function of physical activity levels was then analyzed.  Additionally, improvements in death rates associated with increasing levels of physical activity were also compared with improvements in death rates associated with smoking cessation among these men, which makes this very long-term prospective clinical research study very unique.

One particularly important finding of this study was that the men who continued to live a sedentary lifestyle were twice as likely to die prematurely as the men who began the study in the “high level of physical activity” group, which is consistent with the findings of other similar public health studies.  When looking more closely at each of the three groups of men, based upon their levels of physical activity, the researchers found that the risk of death (mortality) over a period of approximately 35 years was 27, 24, and 18 per “1,000 person-years” of life among the men with low, medium and high levels of physical activity, respectively.  The men who increased their levels of physical activity from “low activity” to “high activity” experienced a 32 percent relative reduction in their risk of mortality, while the “low activity” physical activity group of men who increased their level of physical activity to the “medium” level experienced a 22 percent relative reduction in their risk of death.  A critically important observation in this study was that after 10 years of “high” level physical activity, the middle-aged men who had began this study while in the “low activity” group had attained a death rate that was essentially identical to that of the men who had been in the “high activity” group from the very beginning of this study.  It should also be noted that during the first 5 years of increased exercise and physical activity, the men who had transitioned from the “low activity” group to the “high activity” group actually had a somewhat higher level of mortality when compared to the men who were already in the “high activity” group at the beginning of the study.  After 10 years of sustained “high” level physical activity, however, the men who had started out in the “low activity” group had achieved the same approximately 50 percent reduction in mortality (when compared to the men who remained in the “low activity” group) as was observed in the men who had been in the “high activity” group from the very beginning of this very long-term clinical research study.

Improvements in mortality rates for this cohort of middle-aged men as a result of smoking cessation were also evaluated and, in turn, were compared with the improvements in mortality rates that were observed among the men who boosted their physical activity levels during the course of this study.  Cessation of smoking for 10 years reduced the risk of death in these men by about 40 percent (when compared to the men who continued to smoke), while increasing one’s level of physical activity from the lowest level to the highest level resulted in a 49 percent reduction in mortality after 10 years.  One important limitation of this study is, of course, that women were not included.  However, while the exact magnitude of benefit from increased levels of physical activity may or may not be identical between men and women, there is ample clinical research data available showing that mortality rates decline for both men and women with increasing levels of regular physical activity.

In summary, this important public health study has shown that sedentary middle-aged men who increase their levels of regular physical activity (from “low activity” to “high activity”) for at least 10 years are able to achieve the same level of mortality risk reduction (when compared with men who continue to live a sedentary life) as is observed in other middle-aged men who have spent at least 35 years exercising at the same high level.  Moreover, improvements in mortality among middle-aged men who change from low levels to high levels of regular physical activity for at least 10 years appears to be comparable to giving up smoking for at least 10 years.  The twin lessons from this study are, therefore, that (1) it is never too late to get up off of the couch and start exercising if you want to maximally reduce your risk of premature death, and (2) throwing away your cigarettes will also significantly decrease your risk of an early and otherwise preventable death (needless to say, implementing both of these important lifestyle changes will tremendously reduce your risk of an early and preventable death!).  As a reminder, I recommend that you receive a thorough physical examination by your physician before you embark on a new exercise program, and that you begin your new fitness program in a gradual, graded manner to reduce your risk of injury. 

Disclaimer:  As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity

 

Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and the Physician-in-Chief for Surgical Oncology at the Kaiser Permanente healthcare system in Orange County, California

  

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