Today I'll point out a recent selection of studies on lifestyle choices and life expectancy: the costs of bad choices and the benefits of good choices. The numbers are not particular new, but it is good to be occasionally reminded of the bounds of the possible when it comes to choice versus technology. It is impossible to reliably live to 100 through the use of exercise, diet, and other good lifestyle choices. The best you can do is to change your odds from being low to being slightly less low. Lifestyle choices are not the primary driver of your future longevity. According to the actuarial community, the chance of living to 100 is 10-15% for people in the middle of life now, as opposed to 1% or so for people born a century ago. This difference is due to the progress in every area of medical technology that has produced 150 years of a gentle upward slope in adult life expectancy. If projecting that trend outwards for the rest of our lives at the same steady pace one arrives at these odds. This is the primary business of actuaries, to provide these conservative models of the future.
It is highly unlikely that this trend will in fact continue at the same pace, however, and actuaries have increasingly hedged their pronouncements for more than a decade now. Everything accomplished to date in the extension of human life expectancy has been an incidental byproduct, a side-effect of initiatives that did not deliberately target or address the root causes of aging. Aging is a consequence of cell and tissue damage and we are in the midst of a transition towards research and therapies that can slow or repair this damage; treating aging as a medical condition and working deliberately to bring it under control, in other words. The different between the past and the future of aging will be the difference between a problem left to run untended and a problem that people are actively trying to fix. The trend in life expectancy will leap to the upside in decades ahead.
The evidence suggests that the range in human life expectancy that is under our control through common lifestyle choices is somewhere in the vicinity of fifteen to twenty years. An exemplary set of choices might add five to ten years to life expectancy, and a truly terrible set of choices loses five to ten years from the baseline average. Why does this matter, beyond the obvious? It matters because we live in an age of revolutionary, rapid progress in biotechnology, through the present state of regulation ensures that what happens in the laboratory is only slowly making it to the clinic. Despite the regulatory ball and chain, a few years of life might one day make the difference between being able to benefit from a new rejuvenation therapy, and thus gaining health and additional years, or dying too soon. Ahead of us is the upward curve of technology versus the downward curve of individual mortality. Some people will reach the point at which medical technology keeps them alive and in good health for long enough to reach the era of agelessness, when aging can be completely controlled through comprehensive periodic repair of molecular damage. This is the primary reason as to why it is worth living a better lifestyle rather than a worse lifestyle - quite aside from the other benefits, such as a longer life, better health, lower lifetime medical expenditure, and so on.
In the study, 44 adults ranging in age from 40 to 85 (mean age: 62.6) with mild memory changes but no dementia underwent an experimental type of PET scan to measure the level of plaque and tangles in the brain. Researchers also collected information on participants' body mass index, levels of physical activity, diet and other lifestyle factors. Plaque, deposits of a toxic protein called beta-amyloid in the spaces between nerve cells in the brain; and tangles, knotted threads of the tau protein found within brain cells, are considered the key indicators of Alzheimer's. The study found that each one of several lifestyle factors - a healthy body mass index, physical activity and a Mediterranean diet - were linked to lower levels of plaques and tangles on the brain scans. Earlier studies have linked a healthy lifestyle to delays in the onset of Alzheimer's. However, the new study is the first to demonstrate how lifestyle factors directly influence abnormal proteins in people with subtle memory loss who have not yet been diagnosed with dementia. Healthy lifestyle factors also have been shown to be related to reduced shrinking of the brain and lower rates of atrophy in people with Alzheimer's.
Researchers divided 52 overweight, middle-aged men and women into three groups - those who dieted, exercised or did both - and charged them with losing about 7 percent of their body weight during a 12-14 week period. Those who exclusively dieted or exercised were told to decrease their food intake by 20 percent or increase their activity levels by 20 percent. Those who did both were told to eat 10 percent less and move 10 percent more. The researchers analyzed how the changes affected indicators of cardiovascular health, such as blood pressure, heart rate and other markers for heart disease and stroke, like high "bad" cholesterol levels. They found the three strategies were equally effective in improving cardiovascular health, and were expected to reduce a person's lifetime risk of developing cardiovascular disease 10 percent - from 46 percent to 36 percent.
"Because our previous research and that of others indicates that exercise and diet each provide their own unique health benefits beyond those that were evaluated in the current study, it is important to recognize that both diet and exercise are important for health and longevity. While our study did not find additive benefits of calorie restriction and exercise on traditional risk factors for cardiovascular disease, much of the actual risk of developing cardiovascular disease cannot be accounted for by traditional risk factors. Therefore, our findings don't preclude the possibility that dieting and exercise have additive effects for reducing the likelihood of developing cardiovascular disease. Furthermore, an inactive lifestyle itself is a risk factor for cardiovascular disease, although the physiologic mechanisms for this effect are unknown."
It is difficult to compare directly the practical effects of lifestyle modifications and antihypertensive medications on reducing cardiovascular disease (CVD). The purpose of this study was to compare the hypothetical potential of lifestyle modifications with that of antihypertensive medications in reducing CVD in an aging society using a success rate-oriented simulation. We constructed a simulation model for virtual Japanese subpopulations according to sex and age at 10-year intervals from 40 years of age as an example of an aging society. The fractional incidence rate of CVD was calculated as the product of the incidence rate at each systolic blood pressure (SBP) level and the proportion of the SBP frequency distribution in the fractional subpopulations of each SBP. If we consider the effects of lifestyle modifications on metabolic factors and transfer them onto SBP, the reductions in the total incidence rate of CVD were competitive between lifestyle modifications and antihypertensive medications in realistic scenarios. In middle-aged women, the preventive effects of both approaches were limited due to a low incidence rate. In middle-aged men and extremely elderly subjects whose adherence to antihypertensive medications is predicted to be low, lifestyle modifications could be an alternative choice.
Unhealthy habits are costing Canadians an estimated six years of life. Researchers found that smoking, poor diet, physical inactivity, and unhealthy alcohol consumption contribute to about 50 percent of deaths in Canada. The study found: 26 per cent of all deaths are attributable to smoking; 24 per cent of all deaths are attributable to physical inactivity; 12 per cent of all deaths are attributable to poor diet; 0.4 per cent of all deaths are attributable to unhealthy alcohol consumption. For men, smoking was the top risk factor, representing a loss of 3.1 years. For women it was lack of physical activity, representing a loss of 3 years. The researchers also found that Canadians who followed recommended healthy behaviours had a life expectancy 17.9 years greater than individuals with the unhealthiest behaviours.