George Brooks has been trying to reshape thinking about lactate—in the lab, the clinic and on the training field—for more than 40 years, and finally, it seems, people are listening. Lactate, it's becoming clear, is not a poison, it's the antidote.
In a recent article in the journal
Cell Metabolism, Brooks, a professor of integrative biology at the University of California, Berkeley, reviews the history of the misunderstanding of lactate—often called lactic acid—a small molecule that plays a big role in metabolism. Typically labeled a "waste" product produced by muscles because lactate rises to high levels in the blood during extreme exercise, athletic trainers and competitive athletes think of lactate as the cause of muscle fatigue, reduced performance and pain.
Starting in the 1970s, however, Brooks, his students, postdoctoral fellows and staff were the first to show that lactate wasn't waste. It was a
fuel produced by muscle
cells all the time and often the preferred source of energy in the body: The brain and heart both run more efficiently and more strongly when fueled by lactate than by glucose, another fuel that circulates through the blood.
"It's a historic mistake," Brooks said. "It was thought that lactate is made in muscles when there is not enough oxygen. It has been thought to be a fatigue agent, a metabolic waste product, a metabolic poison. But the classic mistake was to note that when a cell was under stress, there was a lot of lactate, then blame it on lactate. The proper interpretation is that lactate production is a strain response, it's there to compensate for metabolic stress. It is the way cells push back on deficits in metabolism."
