According to a recent study by Lanza et al., endurance exercise increases mitochondrial protein levels, metabolic enzyme activity, and expression of SIRT3 (a sirtuin thought to be involved in longevity assurance). At the organismal level, insulin sensitivity goes up (this is good: insulin resistance leads to type II diabetes) and gluconeogenesis goes down.
So far, so good, but hardly surprising: file under “exercise is good for you, item #68232”. The interesting bit is that the mitochondrial and other changes are very similar to the physiological consequences of calorie restriction (CR), an intervention that is known to extend lifespan in model organisms and to delay age-related disease in humans. The authors argue that exercise may promote longevity through the same pathways as CR.
This fits in nicely with recent observations connecting exercise and CR: for example, resveratrol, thought to be a CR mimetic, improves exercise tolerance in mice, consistent with the idea that exercise and CR have something in common.
The next obvious question: Do exercise mimetics also promote longevity, and if so, do they do so by the same mechanism as CR?