What causes lactic acid?

Are you curious as to why you feel that burning sensation in your muscles after a strenuous workout? Do not worry, it is not the devil trying to possess your body. The reason behind this uncomfortable experience is due to the accumulation of lactic acid.

Before we delve deeper into what happens during exercise that leads to excess production of lactic acid, let us first understand the basics.

What exactly is Lactic Acid?

Lactic acid or lactate salt is an organic compound with LA as its chemical formula. It is derived from pyruvate in one step through enzymatic reduction by either pyruvate dehydrogenase (E1) or lactate dehydrogenase (LDH). Its systematic name could make your head spin-2-hydroxypropanoic acid.

During normal cellular respiration, glucose undergoes a series of reactions and transformations within the mitochondria which ultimately produce ATP(adenosine triphosphate) used for cellular work. However, under anaerobic conditions where oxygen used in this process becomes insufficient, the end-product pyruvic-acid undergoes conversion into lactic-acid catalyzed by enzyme lactate-dehydrogenase(LDH).

Types of Lactates

If you thought there’s just one type of Lactate – like skimmed milk and whole milk – You’re wrong (sad trumpet music playing), because much like dairy products there are different variants:


This type exists naturally in our bodies and can be converted back to glucose when required through gluconeogenesis-our hero against hypoglycemia.


It cannot be metabolized by human cells but rather feeds bacterial colonies found mainly in intestines leading quickly towards cheesy sensations and potentially serious medical conditions if unchecked. Remember kids always go easy on cheese!

So now that we know what Lactic acid is, let us delve into the scientific nitty-gritty of what causes its accumulation.

What causes an increase in lactic acid?


As you probably suspected, physical activity increases the production and accumulation of lactic acid. The hardworking muscle cells during intense exercise require energy to function sufficiently; however, with insufficient oxygen due to aerobic respiration pathways they mainly rely on other sources such as anaerobic Glycolysis which uses glucose but produces only 2 ATP molecules compared to Aerobically produced 36-38 per glucolitic cycle.

What does this mean for our body? An increased cellular energy demand causes a fast oxidative-reductive pathway switch resulting in higher than normal lactate build-up known commonly known as muscular fatigue or “burning.”

Oxygen deprivation: Is less really more?

The body’s preferred source of fuel is – You guessed it- Oxygen. While Its lack doesn’t cause
‘’rusty nails” a term describing painful feelings during workout if available Body prioritizes its usage over Non-aerobic processes.

Oxygen depriving situations like high altitude environments could make your muscles susceptible to Rapid onset fatigue hence inducing lactic-acidosis due to low oxygen supply inhibiting efficient pyruvate oxidation leading instead towards heavy reliance on glycolysis…Yes quite heavy!

Reduce air pressure reduces ambient oxygen supplied thus increasing overall difficulty levels for athletes performing there increasing LA concentrations within blood then –causing “parachute-less skydiving” feeling in their legs.

Sugar Rush

Do not be alarmed when consuming sugary snacks leads you down the same path as Mr.Burns from ‘The Simpsons’ because much like him excess sugar intake can result in detrimental effects (cue spooky music)

The lack of exercise combined with consumption of sugary processed foods may lead directly toward elevated lactate secretion levels without any real work output.

Conclusion: Are we still burning?

So, dear reader while Exercise and oxygen deprivation may cause pain in our muscles due to lactate accumulation this usually goes down once the activity has stopped.

However, if you feel a sharp stab accompanied by abnormal heart rate or severe burn injuries it is advisable to seek immediate medical attention because – well- that’s definitely not lactate-caused!

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