What Is Lactic Acid And How Does It Affect Your Body?

What Is Lactic Acid?

Lactic acid (or lactate) is a natural compound produced when your body breaks down carbohydrates for energy, especially under low-oxygen (anaerobic) conditions. Your muscles, red blood cells, brain, and skin tissues create it as part of normal metabolism.

It functions as an emergency energy source that helps sustain cellular activity when oxygen delivery is limited. During intense activity, when your tissues need more energy than oxygen can supply, your body shifts to anaerobic metabolism and increases lactic acid production to keep cells functioning.

What Does Lactic Acid Do in the Body?

Lactic acid plays three key roles in the body. It provides quick energy when oxygen is limited, especially during intense physical activity. It also helps the liver produce glucose through gluconeogenesis, supporting steady blood sugar levels and fuelling vital organs. Additionally, lactic acid acts as a signalling molecule, guiding immune responses and helping the body manage stress and maintain balance.

Lactic Acid and Exercise: Role in Muscle Fatigue

During high-intensity exercise, your muscles produce more lactic acid because oxygen supply can’t keep up with energy needs. But several misconceptions surround its role:

• Temporary build-up: Lactic acid accumulation is normal and short-lived.
• Energy support: It helps maintain energy production when oxygen is limited.
• Not the cause of burn: The burning sensation during intense exercise results from the accumulation of hydrogen ions and not from lactic acid itself.
• Fast removal: Your body clears lactic acid within about an hour after activity.
• No link to soreness: It does not cause delayed-onset muscle soreness (DOMS).

The Role of Lactic Acid in Heart Disease

Abnormal lactate levels can serve as a marker of how effectively your heart and tissues receive and utilize oxygen. When the heart struggles to pump efficiently, as seen in heart disease, cells produce more lactic acid due to insufficient oxygen. Persistently high levels may signal severe tissue stress.

Lactic Acid and Heart Attack Recovery

After a heart attack, the damaged heart muscle may temporarily rely more on lactate as an energy substrate because it isn’t receiving enough oxygen. Doctors often monitor lactic acid levels to assess recovery and detect ongoing tissue stress. If levels remain high, it can signal continued oxygen deprivation in the heart, requiring prompt medical attention to prevent further damage.

Lactic Acid in Congestive Heart Failure (CHF)

In congestive heart failure, reduced pumping efficiency means less oxygen reaches your tissues. This oxygen shortage triggers increased lactic acid production throughout your body, signalling metabolic stress and potentially worsening heart function. Regular monitoring of lactic acid levels helps healthcare providers assess congestive heart failure progression and adjust treatment strategies accordingly.

How Lactic Acid Affects Your Skin

Lactic acid offers several benefits for skin health when used in cosmetic applications:

• Gentle exfoliation: Removes dead skin cells effectively.
• Enhanced renewal: Promotes healthy skin cell turnover.
• Improved hydration: Draws moisture into the skin’s upper layers.
• Even tone: May help reduce dark spots and improve overall complexion.

The Difference Between Lactic Acid and Lactate

While often used interchangeably, lactic acid and lactate are technically different. Lactic acid represents the acid form, whilst lactate is its ionised version that predominates at your body's normal pH levels. In exercise physiology discussions, "lactate" is more scientifically accurate, though both terms describe the same metabolic process.

Signs You Might Have Too Much Lactic Acid

Excessive lactic acid accumulation, called lactic acidosis, can cause concerning symptoms:

• Digestive issues: Nausea, vomiting, and abdominal pain
• Breathing changes: Rapid breathing or shortness of breath
• Physical weakness: Muscle weakness and persistent fatigue
• Neurological symptoms: Confusion, lightheadedness, or irregular heartbeat

According to StatPearls (Lactic Acidosis, 2025), lactic acidosis is defined as a serum lactate concentration greater than 4 mmol/L with an arterial pH below 7.35, and it is one of the most common causes of metabolic acidosis in critically ill patients, with persistent high lactate strongly associated with increased mortality.

Can Lactic Acid Cause Muscle Soreness?

Contrary to popular belief, lactic acid does not cause delayed-onset muscle soreness. Post-exercise muscle discomfort results from microscopic muscle damage and subsequent repair processes, not lactic acid accumulation. Your body clears lactic acid from muscles within approximately one hour after exercise completion.

Medical Tests for Measuring Lactic Acid Levels

Healthcare providers use several methods to measure lactic acid:

• Blood lactate test: Measures lactate concentration in blood samples.
• Arterial blood gas analysis: Assesses acidity, oxygen, and carbon dioxide levels, including lactate.
• Venous blood sampling: A less invasive option still providing useful lactate measurements.

• Serum Electrolyte Test: Evaluates hydration status, electrolyte balance, and contributes to assessment of acid-base disturbances.

• Comprehensive Metabolic Panel (CMP): Helps evaluate metabolic function, organ health, and electrolyte balance.

Lactic Acid and Diet: Foods That Can Help Reduce It

Certain dietary choices may support healthy lactic acid levels:

• Adequate hydration: Water helps facilitate lactic acid removal.
• Vitamin B–rich foods: Support energy metabolism and muscle function.
• Magnesium sources: May assist muscle relaxation and recovery.
• Antioxidant-rich produce: Fruits and vegetables help reduce oxidative stress.

Lactic Acid as a Chemical in Cosmetics

Commercial lactic acid serves various cosmetic purposes:

• Chemical exfoliation: Commonly used in peels and anti-aging formulations to improve skin texture and tone
• Moisturising effects: Included in hydrating skincare products
• Acne treatment: May help address breakouts and hyperpigmentation
• Skin irritation risk: Overuse can cause redness or sensitivity.

Lactic Acid: Benefits and Risks

There are several advantages and side effects of lactic acid:

Benefits:
• Provides essential energy during intense physical activity.
• Supports glucose production and immune system responses.
• Offers effective skincare exfoliation and hydration.

Risks:
• Excessive accumulation can lead to dangerous lactic acidosis.
• Cosmetic overuse may cause skin irritation.
• Chronically high levels might indicate serious health conditions.

Conclusion

Lactic acid plays an important role in energy production and metabolic balance. Understanding how it builds and clears helps you manage muscle fatigue and improve performance. But persistently high levels, especially in people with heart disease or recovering from a heart attack, need timely medical evaluation. With proper hydration, pacing, and recovery, your body efficiently regulates lactic acid for better training, faster recovery, and overall healthier movement.

Metropolis Healthcare offers a convenient and reliable way to stay informed with 4000+ tests, full body checkups, speciality diagnostics, and quick, accurate home sample collection through a network of 10,000+ touchpoints. You can book easily via our website, app, WhatsApp, or a simple phone call, ensuring trusted results delivered with care right to your doorstep.

FAQ

What are the symptoms of lactic acidosis?

Symptoms include rapid breathing, nausea, vomiting, sweating, muscle weakness, and feeling extremely tired. Severe cases can cause low blood pressure and confusion.

Can lactic acid build-up be harmful?

Yes. While normal levels are safe, a significant build-up may indicate serious health problems like heart disease, infection, or metabolic disorders.

What causes high lactic acid in the blood?

Intense exercise, heart failure, severe infections, low oxygen levels, uncontrolled diabetes, or certain medications can raise lactic acid levels.

How does lactic acid affect heart health?

In conditions like heart disease, heart attack, and congestive heart failure, reduced oxygen supply forces cells to produce more lactic acid. Monitoring levels helps assess disease severity and tissue oxygenation.

References

• https://www.ncbi.nlm.nih.gov/books/NBK470202/
• https://my.clevelandclinic.org/health/diseases/25066-lactic-acidosis
• https://medlineplus.gov/ency/article/000391.htm
• https://www.healthline.com/health/lactic-acidosis
• https://www.webmd.com/fitness-exercise/exercise-and-lactic-acidosis