I believe (through a great deal of reading) that any endurance exercise is pro-aging, such as running or biking for longer than 30 minutes at more than 50-60% of max capacity.
Depending on what you mean by "aging", that is contrary to an awful lot of data. The effect of exercise on longevity (which is not necessarily the same as aging) is presumably what most interests people, and there is strong evidence that vigorous endurance exercise prevents disease and extends life.
There is the Harvard Alumni Health Study
http://jama.ama-assn...act/273/15/1179Exercise intensity and longevity in men. The Harvard Alumni Health Study
I. M. Lee, C. C. Hsieh and R. S. Paffenbarger Jr
Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
OBJECTIVE--To examine the independent associations of vigorous (> or = 6 resting metabolic rate [MET] score) and nonvigorous (< 6 MET score) physical activity with longevity. DESIGN--Prospective cohort study, following up men from 1962 or 1966 through 1988. SETTING/PARTICIPANTS--Subjects were Harvard University alumni, without self-reported, physician-diagnosed cardiovascular disease, cancer, or chronic obstructive pulmonary disease (n = 17,321). Men with a mean age of 46 years reported their physical activities on questionnaires at baseline. MAIN OUTCOME MEASURE--All-cause mortality (3728 deaths). RESULTS--Total energy expenditure and energy expenditure from vigorous activities, but not energy expenditure from nonvigorous activities, related inversely to mortality. After adjustment for potential confounders, the relative risks of dying associated with increasing quintiles of total energy expenditure were 1.00 (referent), 0.94, 0.95, 0.91 and 0.91, respectively (P [trend] < .05). The relative risks of dying associated with less than 630, 630 to less than 1680, 1680 to less than 3150, 3150 to less than 6300, and 6300 or more kJ/wk expended on vigorous activities were 1.00 (referent), 0.88, 0.92, 0.87, and 0.87, respectively (P [trend] = .007). Corresponding relative risks for energy expended on nonvigorous activities were 1.00 (referent), 0.89, 1.00, 0.98, and 0.92, respectively (P [trend] = .36). Analyses of vigorous and nonvigorous activities were mutually adjusted. Among men who reported only vigorous activities (259 deaths), we observed decreasing age-standardized mortality rates with increasing activity (P = .05); among men who reported only nonvigorous activities (380 deaths), no trend was apparent (P = .99). CONCLUSIONS--These data demonstrate a graded inverse relationship between total physical activity and mortality. Furthermore, vigorous activities but not nonvigorous activities were associated with longevity. These findings pertain only to all-cause mortality; nonvigorous exercise has been shown to benefit other aspects of health.
A later analysis of the data showed a protective effect against coronary artery disease specifically
http://circ.ahajourn.../full/102/9/975Conclusions—Total physical activity and vigorous activities showed the strongest reductions in CHD risk. Moderate and light activities, which may be less precisely measured, showed nonsignificant inverse associations. The association between physical activity and a reduced risk of CHD also extends to men with multiple coronary risk factors.
Then there's the Stanford University study
http://win.niddk.nih...physicalfit.htmPhysical Fitness Level: Best Predictor of Death in Men
After adjusting for age, the best predictor of death among all subjects was peak exercise capacity, measured in metabolic equivalents, or MET... Among all subjects, researchers calculated that a 1-MET increase in exercise capacity yielded a 12 percent improvement in survival.
And the same thing is observed in women
http://www.cbass.com...isecapwomen.htmThere is a good summary here
http://www.pponline..../encyc/0003.htmWithin limits, exercise's protective effects tend to expand as you increase your quantity of exercise. Jogging just 10 miles per week improves your chances of living longer rather dramatically, compared to completing no exercise at all. Covering 25 to 30 miles each week lowers your risk of dying even more. Beyond 30 miles, though, there's little evidence that more miles limit the grim reaper's activities any further.
Ralph Paffenbarger, M.D., one of principal investigators in the Harvard Alumni Study, summarises the benefits of exercise with a neat formula: For each hour that a person exercises, he/she gets roughly two extra hours of life! Paffenbarger's proposition is true only for reasonable amounts of exercise, though (probably for up to 30 weekly miles of running). Otherwise, immortality could be 'purchased' simply by exercising for slightly more than 12 hours each day, which would 'buy back' the lost 24-hour period.
Note this especially
The type of exercise you choose matters when it comes to longevity. Recent research from Finland indicates that individuals who engage in endurance activities (running, cycling, swimming, cross country skiing, walking) live about six years longer than couch potatoes. In contrast, those who prefer team sports like basketball, ice hockey, or soccer live just four years more. And sports-active people who prefer 'power-type' activities, including weight lifting, field events, and sprinting, last for only two additional years.
However, most of the increase in lifespan enjoyed by the Finnish team-sport and power athletes is due to social status, not athletic activity (team and power athletes tend to enjoy greater social status than sedentary people, which gives them better living conditions, higher-quality food, and superior health care). When the influence of social status is removed from the analysis, only athletic-minded individuals who routinely engage in endurance-type activities enjoy greater longevity than the Finnish non-exercisers. The key difference is that participation in endurance exercise makes it highly unlikely that someone will keel over between the ages of 50 and 69. Such deaths, which occur more frequently in the team-sport, power-sport, and sedentary groups, are shifted into the seventh decade of life in those who huff and puff while running, skiing, cycling, or walking several times each week.
For most people reading this, not "keeling over between the ages of 50 and 69" is going to be the biggest determinant of whether they live to reach "escape velocity" in biogerontological research later this century. Therefore whatever effect endurance exercise has on intrinsic aging is pratically moot. I believe that staying away from intense exercise or endurance exercise based on simplistic intuitions about wear-and-tear, which seems to be where this thread it going, is a bad idea. Yes, joints can be an issue. But joints are more easily replaced than coronary arteries, and they won't kill you in the process of failing.
