While a lifestyle that includes lots of exercise helps you live longer, the effect is not very impressive. According to the animal study that Spanish physiologists have published in Longevity & Healthspan, exercise does have a more convincing positive health effect in old age.
The researchers, working at the University of Valencia, put one group of mice in a cage with a treadmill, and another group of mice in a cage without a treadmill. When the mice were young they ran 4.6 km a day. In old age they only ran 0.6 km per day.
The mice that could exercise if they wished lived to be on average 3 percent older than the mice that had no treadmill in their cage. So the effect of voluntary exercise on lifespan was negligible.
While physical exercise hardly extended lifespan in this study, the effect of exercise on the health of the mice was more impressive.
In the first figure below you can see how the amount of BDNF in the brains decreased dramatically in sedentary mice, but not in active mice. BDNF is a hormone-like substance that forces brain cells to develop. More BDNF means less likelihood of dementia and depression.
Although running doesn’t do much to develop the muscles in mice’s claws, running did reduce the decrease in strength in these muscles, as the second figure below shows.
Aging reduces our coordination ability. In a test in which the mice had to climb over a cord without falling, the mice that had exercised scored better than the sedentary mice, as the third figure shows.
And finally, the fourth figure shows that the mice that ran had a better condition: they were capable of developing a higher maximal speed.
“Lifelong spontaneous exercise does not prolong lifespan but improves healthspan in mice”, the researchers write. “Exercise is an intervention that enhances function and delays frailty in experimental animals. These results stress the importance of this intervention to prevent human frailty and dependency.”
Life-long spontaneous exercise does not prolong lifespan but improves health span in mice.
Life expectancy at birth in the first world has increased from 35 years at the beginning of the 20th century to more than 80 years now. The increase in life expectancy has resulted in an increase in age-related diseases and larger numbers of frail and dependent people. The aim of our study was to determine whether life-long spontaneous aerobic exercise affects lifespan and healthspan in mice.
Male C57Bl/6J mice, individually caged, were randomly assigned to one of two groups: sedentary (n = 72) or spontaneous wheel-runners (n = 72). We evaluated longevity and several health parameters including grip strength, motor coordination, exercise capacity (VO2max) and skeletal muscle mitochondrial biogenesis. We also measured the cortical levels of the brain-derived neurotrophic factor (BDNF), a neurotrophin associated with brain plasticity. In addition, we measured systemic oxidative stress (malondialdehyde and protein carbonyl plasma levels) and the expression and activity of two genes involved in antioxidant defense in the liver (that is, glutathione peroxidase (GPx) and manganese superoxide dismutase (Mn-SOD)). Genes that encode antioxidant enzymes are considered longevity genes because their over-expression may modulate lifespan. Aging was associated with an increase in oxidative stress biomarkers and in the activity of the antioxidant enzymes, GPx and Mn-SOD, in the liver in mice. Life-long spontaneous exercise did not prolong longevity but prevented several signs of frailty (that is, decrease in strength, endurance and motor coordination). This improvement was accompanied by a significant increase in the mitochondrial biogenesis in skeletal muscle and in the cortical BDNF levels.
Life-long spontaneous exercise does not prolong lifespan but improves healthspan in mice. Exercise is an intervention that delays age-associated frailty, enhances function and can be translated into the clinic.
PMID: 24472376 [PubMed] PMCID: PMC3922914