Often blamed for the burn you experience during intense exercise, research has shed a completely different light on lactic acid.
Here are 6 need-to-knows about lactic acid
1. The theory that lactic acid caused fatigue was based on 1920's research
The notion that blood lactate triggered fatigue was based on research conducted in the 1920's where a decrease in pH reduced muscle cell excitability and contractile force.
However, advances in technology and continuing research have determined that lactate offers a wide range of physiological benefits, which makes the 1920's research seem outdated.
2. Lactic acid is technically called something else
While it does play a role in controlling blood PH, technically, lactic acid should be referred to as lactate, or blood lactate.
3. Muscle fatigue is not just caused by lactate build up
Exercise places large demands on the body, especially the systems that produce energy to fuel our activity.
When exercise continues over a long duration, or is at a high level of intensity, energy production struggles to keep up with demands.
The primary energy systems are aerobic, meaning with oxygen, and anaerobic, or without oxygen. The oxygen system tends to be used for longer duration activities, while more intense activities rely on the anaerobic system.
A by-product of energy production is a build up of blood lactate (generated from the anaerobic breakdown of glycogen - without oxygen).
Research suggests that lactate is a biomarker of fatigue because it accumulates during high-intensity exercise, yet it may not cause muscular fatigue. There are a wide range of other noxious metabolites such as phosphate and potassium that have been identified as the primary causes of fatigue, rather than lactate.
READ MORE: Why you get tired when you run
4. Lactate may actually boost athletic performance
Modern science has determined that lactate is a valuable energy source for physiological systems such as the brain, heart and skeletal muscle, and it can offer these benefits both during exercise, and at rest.
In fact, lactate is an important component in the complex biochemical processes which acts to counteract the muscular fatigue process. Researchers have claimed that lactate is not a waste product of anaerobic metabolism, but rather a useful alternative energy source.
5. Increased fitness may further improve the benefits of lactate
The body's ability to utilise lactate and improve athletic performance may improve as fitness levels improve. Researchers found an 18 fold increase in net lactate utilaation in response to exercise.
6. More research is needed to fully understand the role of lactate and human performance
While our understanding of lactate has improved, and modern science has helped to dispel some well held myths about lactic acid, more research is needed.
As recently as 2014, scientists acknowledged that additional studies and further research is needed to develop a better understanding of how lactate improves sports performance, and it role in brain function during exercise.
There has also been conflicting evidence in some studies, and further research is required to help clarify the interaction between lactate and temperature.
Source: Todd JT. Lactate: valuable for physical performance and maintenance of brain function during exercise. Bioscience. 2014. Vol 7. doi: 10.1093/biohorizons/hzu001