Actually, think you summarized it more correctly here:
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These probably speak to that question:
Exercise has been shown to protect from many age-related diseases but fails to extend maximum life span in rodents (16, 17, 21).
Although the evidence clearly shows a greater benefit from calorie restriction compared with exercise on longevity, there remains a significant gap in the literature explaining this disparate effect. The effects of calorie restriction (40) and exercise (6) on age-related diseases and markers of aging have been exhaustively studied independently, while only a limited number have examined calorie restriction and exercise in tandem (26, 36).
Rodent (17) and human studies (32) suggest that increasing energy expenditure via exercise fails to mimic the life-prolonging benefit of consuming fewer calories.
These results showed that mild and moderate calorie restriction were more effective at lowering fasting IGF-1 and insulin levels than exercise, and animals on moderate calorie restriction most closely resembled young animals for measures of hormones and stress-related proteins. In contrast, exercised animals were leaner than calorie-restricted mice and exhibited greater tissue levels of HSPs and oxidative phophorylation complex content in skeletal muscle mitochondria.
Thus, it is possible that some harmful byproduct(s) or consequence(s) associated with exercise “interferes” with the beneficial effects of being lean. Alternatively, calorie restriction may extend life span by a mechanism(s) independent of leanness, and exercise may fail to activate these critical pathways to the same scope or magnitude.
Recently, Fontana and colleagues (10–12) have examined systemic biomarkers in individuals on a selfimposed low-calorie or low calorie-low protein diet vs. individuals engaged in high-volume exercise for several years. Despite a similar body mass index (10, 12) or fat content (11), long-term calorie restriction and exercise resulted in disparate effects on various parameters related to aging, including thyroid function, systemic inflammation, and growth factors. For instance, individuals engaged in voluntary calorie restriction were found to have lower levels of serum T3 and TNF-α levels than exercisers or a control group consuming a typical Western diet (11). In another study, individuals consuming a low calorie-low protein diet were shown to have a more favorable cancer risk profile than endurance runners or controls, including lower serum IGF-1 and greater levels of dehydroepiandrosterone sulfate and sex-hormone-binding globulin (10). Furthermore, a low-calorie vegan diet resulted in lower blood pressure than exercisers (12). Taken together, the present investigation, coupled with these related studies in humans suggest that at the same relative energy deficit, exercise fails to completely mimic the beneficial changes associated with calorie restriction.
Therefore, the available evidence demonstrates that an increase in energy expenditure can attenuate disease risk (20, 22) but does not presently support the notion that an energy expenditure-induced energy deficit slows the rate of biological aging (20).
- Rats that exercise regularly will, on average, live longer compared to a group that eats the same amount but does not exercise. This is because exercise prevents some diseases, which allows more individual animals to live out their expected life span.
- However, when comparing the rats in these two groups that eat the same amount, the longest-lived animals in the exercise group don’t live any longer than the longest-lived rats in the non-exercise group. Taken together, these findings indicate that exercise can prevent an early death from disease in some rats, but does not extend the maximal lifespan of any of the rats.
- When comparing rats that exercise to those that don’t exercise but eat much less, the longest-lived rats are from the group that ate less.
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