Exercise Provides Benefits By Cleaning Up Metabolic Junk January 22, 2012Posted by Metabiological in Longevity.
Tags: Aubrey de Grey, exercise, longevity, science, SENS
Longevity research is a personal interest of mine (I use the word interest in the intellectual sense, rather than to imply I work on longevity). As such I am always happy to see advances make their way into the news. While the philosophical debates over whether extending human lifespan is desirable will continue regardless of what advances are made on the engineering front the best thing advocates can do to sway public opinion in our favor is to show first and foremost that it is feasible.
Exercise has long been known to promote health and longevity but up until fairly recently we haven’t had a very good idea why it does. Oh sure, we’ve known that it reduces rates of chronic diseases like heart disease, stroke and diabetes and that people who exercise are more likely to live longer, healthier lives but the actual mechanisms still to a large degree elude us. That seems to be changing though and a group of scientists at the Howard Hughes Medical Institute have taken another step forward.
What they’ve found is that exercise triggers a recycling system within our cells, a process known as autophagy:
Autophagy is like a “cellular garbage disposal,” says Howard Hughes Medical Institute investigator Beth Levine, a physician at the University of Texas Southwestern Medical School in Dallas who has been studying the process for more than a decade. The process works like this: First, a double membrane forms around the unwanted cargo inside the cell, enveloping it. This membrane then fuses with an organelle called a lysosome, which contains enzymes that rush in and break down the contents. The bits and pieces created by this process get recycled, providing raw materials for new structures or a burst of energy.
Autophagy keeps cells healthy by “getting rid of all of the obsolete and abnormal structures,” Levine explains. It also helps cells survive lean times. By cannibalizing unwanted proteins and other junk, the cells can get nutrients.
In the study mice which had been engineered to not increase autophagy rates due to exercise or starvation. When compared to normal mice they exhibited lower physical performance and none of the accrued benefits of exercise.
The buildup of cellular junk is one of the mechanisms for aging outlined by Aubrey de Grey in his SENS approach so if nothing else it’s nice to see some vindication for him. Similar research on fasting and drugs like rapamycin have also shown the importance autophagy plays in keeping our cells, and by extension the rest of us, healthy. One study even showed that increased autophagy actually increases total life span compared to normal, though the effect is currently fairly small. The holy grail of course would be a drug or treatment that mimics and improves upon the the effects exercise has on this process, something like the above mentioned rapamycin may be the starting point for.