Wednesday, March 5, 2008

Exercise, eat less and extend your life?

While referring to rats, this is still an interesting study regarding the potential benefits of calorie restriction - of which Intermittent Fasting (IF) is a form - and exercise. Basically there is a problem that as we get older we tend to lose muscle. This study suggests that you can avoid that problem (and its consequences) through lifelong, voluntary exercise combined with mild (8%) caloric restriction.

Anyway, the relevance here is that IF has been shown to have similar results to caloric restriction (CR) which itself has been demonstrated to increase lab rat lifespans more than 20%. I often post IF studies here and am also a fan of resistance exercise. Brad Pillon's Eat Stop Eat, that I've pointed to before, also proposes IF coupled with resistance training.

Lifelong exercise and mild (8%) caloric restriction attenuate age-induced alterations in plantaris muscle morphology, oxidative stress and IGF-1 in the Fischer-344 rat


Muscle atrophy is a highly prevalent condition among older adults, and results from reduced muscle mass and fiber cross-sectional area. Resistive exercise training and moderate (30–40%) caloric restriction may reduce the rate of sarcopenia in animal models. We tested the hypothesis that lifelong, voluntary exercise combined with mild (8%) caloric restriction would attenuate the reduction of muscle fiber cross-sectional area in the rat plantaris. Fischer-344 rats were divided into: young adults (6 mo) fed ad libitum (YAL); 24 mo old fed ad libitum (OAL); 24 mo old on 8% caloric restriction (OCR); lifelong wheel running with 8% CR (OExCR). Plantaris fiber cross-sectional area was significantly lower in OAL than YAL (−27%), but protected in OCR and OExCR, while mass/body mass ratio was preserved in OExCR only. Furthermore, 8% CR and lifelong wheel running attenuated the age-induced increases in extramyocyte space and connective tissue. Citrate synthase activity decreased with age, but was not significantly protected in OCR and OExCR. Total hydroperoxides were higher in OAL than YAL, but were not elevated in OExCR, with out a change in MnSOD. IGF-1 levels were lower in OAL (−57%) than YAL, but partially protected in the OExCR group (+51%).

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