Soreness of your muscles, particularly after a prolonged exercise regimen can be quite debilitating. It happens not just in the gym with heavy lifting but muscles can feel painful and sore even with endurance runs stretching a few miles.

Pain and soreness that develops after a few hours of exercise is called delayed onset muscle soreness or DOMS. It is quite a common phenomenon and differs from exercise related muscle cramps based on the symptoms and timing. Muscle cramps happen quite during the workout itself, rarely a few hours later, whereas DOMS is typically after a few hours have passed after the workout. They differ in the underlying mechanisms as well. DOMS is thought to be due to inflammation from micro-trauma to the muscle fibrils during exercise.

Muscle cramps can happen due to many different conditions but at times, lactic acid (or lactate) build up during training is often considered responsible for this. Other reasons for cramping include magnesium and potassium (electrolyte) deficiency, dehydration (loss of water and nutrients) and repetitive exhaustive movement of muscles leading to neuromuscular fatigue.

What is lactic acid and how does it build up?

Lactic acid (at times referred to lactate) is a product of anaerobic metabolism during exercise- which is essentially metabolism without oxygen (hence anaerobic). When the demand of the body exceeds the supply of oxygen, the body turns to an alternative pathway to generate energy.

Glycogen in the muscle needs to be broken down using a principle called glycolysis which generates ATP, our cellular source of energy. The by-product of that is pyruvate which is converted into lactic acid. Hydrogen ions couple with this acid is called lactate. At times, this byproduct is considered to be the cause of soreness or muscle cramps. This theory, however, is debated.

The lactate diffuses back into circulation from the muscles and is utilized back for generation of energy and is recycled. Liver can convert lactate into bicarbonate. In the absence of enough oxygen, lactic acid builds up. This is true during normal exercise conditions (physiological state) as well as during ischemia – e.g. blockage in the blood supply route (which is pathological).

How to reduce lactic acid build up in muscles

As discussed above, any strenuous exercise causes lactic acid build-up in the muscles. This product however is easily recycled in the circulation. Other than giving you an unpleasant “burning sensation”, this is physiologically a harmless situation.

One of the commonest causes of lactate build up is ischemia or low blood supply. This, in turn can be due to dehydration. Lactate levels are often high in patients presenting to the emergency room with an infection or dehydration. One of the “reflexes” hence in the hospital setting, is to treat the high lactate quickly with adequate hydration of the patient (i.e. with fluid boluses).

Similarly, in athletes who endure in the gym or in the field, lactate build up is common after an exercise stretch. The safest way to keep it to a minimum is by hydrating well, particularly with water and electrolytes, at times with an alkaline solution.

Our body has innate mechanisms to keep the lactic acid under control. As it continues to generate, buffers within the body comprising of phosphates, ammonium and bicarbonate essentially neutralize the acidity and help the kidneys get rid of lactate. A healthy liver easily coverts lactate into bicarbonate keeping the acid-base balance within the body, fairly intact.

Diseases of the kidney, liver, infections, dehydration, and ischemia (compromise of blood supply to internal organs) can raise lactic acid levels in the blood and muscles.

The Bottom Line

Lactic acid is built up in the muscles during strenuous exercise. This is a physiological adaptation and this process serves as an energy source when oxygen demand is not met. Our body recycles this lactate into energy and innate mechanisms keep the level of this acid under control.

Dehydration can worsen elimination of lactate from the kidney and is key to preventing muscle cramps and soreness. Although lactate accumulation has been blamed to be responsible for muscle soreness, this theory is highly debatable.

Lactic acid build-up and muscle soreness, both have one thing in common: heavy exercise. Keeping your body well hydrated, particularly with magnesium infused electrolyte mix such as MAGNAK® can reduce the microtrauma in muscles that is likely responsible for muscle soreness. Learn more about how MAGNAK® can enhance your workouts here!