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28.01.2011

The rejuvenating effect of 45 minutes' running every day: animal study

Old lab rats that run for 45 minutes five times a week in a treadmill become thinner and improve their cardiovascular condition. Nothing new there. But Italian researchers discovered that the mechanism behind the improvement in condition is surprisingly similar to the way calorie restriction works. The simple training schedule activated the longevity enzyme SIRT1.

Calorie restriction
There is a simple but extremely effective way that everyone can use to extend their lifespan by several tens of percent: calorie restriction. Just eat about 30 percent fewer kcal than you really need your whole life and everything will be fine. Well… fine…?

Constant starvation will make you all skin and bones, you won't be able to keep yourself warm, you'll lose strength, libido, reaction time and the ability to concentrate, you'll be continuously tired and there'll be lots more unpleasant effects too. Put simply, your quality of life will be bad. But you'll live longer.

SIRT1
Starvation activates the production of protective enzymes in your cells, and forces the cells to make more effort to repair your genetic material. This reduces the wear and tear in your body and as a result you live longer. It's as simple as that. A key factor in the process is the enzyme SIRT1. So researchers are looking for a way to activate this enzyme that does not involve starving yourself. Candidates are plant-based substances such as resveratrol and EGCG, which in test tubes activate SIRT1.

Study
The Italians discovered that cardio training also boosts SIRT1 when they did experiments with 2-year-old lab rats. Two years is old for a lab rat. The researchers got their animals to run for 8 weeks. A control group of elderly rats did not run. And the researchers used a second control group of young non-active rats.

Results
The table below shows that the training programme made the old rats thinner and made their heart function like that of young rats. BW = body weight; LVW = left ventricular wet weight; HR = heart rate; LVSP = left ventricular systolic pressure.

When the researchers examined the heart muscle of the old rats they saw that the SIRT1 enzyme had become more active. Y = young; O = old; TO = trained & old.

The cells contained less 4-hydroxynonenal [4HNE]. This compound is formed when free radicals damage fatty acids in cell membranes. The catalase concentration was higher. Catalase is a protective enzyme that converts the potentially dangerous radical hydrogen peroxide into water and oxygen. Hydrogen peroxide forms in cells during energy burning processes.

Conclusion
The Italians think that cardio training is a way of at least protecting the heart and blood vessels against diseases of ageing. And maybe there are even more possibilities. They found the same processes in the fat tissue of the rats. It's likely that the rejuvenating effect of exercise is found in all tissues.

By the way, the elderly rats didn't seem to enjoy the exercise. The researchers had to use 'mild electric shocks' to, ahem, motivate the animals. Two rats didn't survive this. But the researchers say this doesn't affect their conclusions, as two animals also died in the non-active elderly group.

Source:
Rejuvenation Res. 2008 Feb;11(1):139-50.

More:
Runners' testes stay young 10.06.2010
Physical exercise delays molecular aging by ten years 25.12.2008