“It’s one of the classic mistakes in the history of science,” Dr. Brooks said.
Its origins lie in a study by a Nobel laureate, Otto Meyerhof, who in the early years of the 20th century cut a frog in half and put its bottom half in a jar. The frog’s muscles had no circulation – no source of oxygen or energy.
Dr. Myerhoff gave the frog’s leg electric shocks to make the muscles contract, but after a few twitches, the muscles stopped moving. Then, when Dr. Myerhoff examined the muscles, he discovered that they were bathed in lactic acid.
A theory was born. Lack of oxygen to muscles leads to lactic acid, leads to fatigue.
Athletes were told that they should spend most of their effort exercising aerobically, using glucose as a fuel. If they tried to spend too much time exercising harder, in the anaerobic zone, they were told, they would pay a price, that lactic acid would accumulate in the muscles, forcing them to stop.
Few scientists questioned this view ~.
When he graduated and began working on a Ph.D. in exercise physiology, he decided to study the lactic acid hypothesis for his dissertation.
“I gave rats radioactive lactic acid, and I found that they burned it faster than anything else I could give them,” Dr. Brooks said. It looked as if lactic acid was there for a reason. It was a source of energy. As for the idea that lactic acid causes muscle soreness, Dr. Gladden said, that never made sense.
In a paper in press for the American Journal of Physiology – Endocrinology and Metabolism, published online in January, Brooks and colleagues ~ link for the first time two metabolic cycles – oxygen-based aerobic metabolism and oxygen-free anaerobic metabolism – previously thought distinct.
“This is a fundamental change in how people think about metabolism,” Brooks said. “This shows us how lactate is the link between oxidative and glycolytic, or anaerobic, metabolism.”
“The world’s best athletes stay competitive by interval training,” Brooks said, referring to repeated short, but intense, bouts of exercise. “The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use it up, it doesn’t accumulate.”
Experiments with dead frogs in the 1920s seemed to show that lactate build-up eventually causes muscles to stop working. But Brooks in the 1980s and ’90s showed that in living, breathing animals, the lactate moves out of muscle cells into the blood and travels to various organs ~.
Brooks always suspected, however, that the muscle cell itself could reuse lactate, and in experiments over the past 10 years he found evidence that lactate is burned inside the mitochondria, an interconnected network of tubes, like a plumbing system, that reaches throughout the cell cytoplasm.
What does this mean for my training? Lactate threshold is the most important determinant of success in endurance-related activities and events, therefore it’s improvement is the main goal of endurance training programs. By performing lactate threshold training, you are also directly increasing the calories you burn during this type of exercise program. This type of training is also highly recommended to enhance weight loss and weight management.
If you’re weightlifting, which is anaerobic, I’m not sure this changes anything. I believe it’s generally accepted that the ideal range is 8-12 reps in 1-3 sets, every other day. This means that one set of eight reps is in range. The main thing is to use the maximum weight that you’re able to lift with good form. When you can do a few more than eight reps, check to see if you can handle more weight.