🧪 What Is Acid-Base Balance?
Acid-base balance is the body's ability to maintain a stable blood pH (normal range: 7.35-7.45). During intense physical exercise, anaerobic glycolysis produces lactic acid (lactate) and hydrogen ions (H+) that lower pH — metabolic acidosis develops. The body has powerful buffer systems that neutralize the increase in acidity and maintain pH homeostasis.
🔬 Buffer Systems
🩸 Bicarbonate System
The main extracellular buffer system. H+ + HCO3- ↔ H2CO3 ↔ H2O + CO2. CO2 is removed through the lungs. Makes up ~50% of buffer capacity.
💪 Muscle Carnosine
Dipeptide (beta-alanine + histidine) acting as an intracellular buffer. Buffers up to 15% of H+ during intense exercise. Beta-alanine supplements increase carnosine content.
🩸 Hemoglobin
Red blood cell protein that buffers H+ and is involved in CO2 transport. Important for returning blood to the lungs.
🧬 Phosphate System
Intracellular buffer, especially important in the kidneys. Less significant during acute acidosis during exercise.
📉 Metabolic Acidosis During Exercise
When exercise intensity exceeds aerobic capacity, anaerobic glycolysis becomes the dominant energy source. During this process, ATP is produced, but the by-product is hydrogen ions (H+). As H+ accumulates, muscle pH falls, causing:
- Enzyme inhibition: Phosphofructokinase (PFK) — the key glycolytic enzyme — is inhibited at low pH. This is a natural "safety valve" that prevents pH from dropping too much.
- Calcium competition: H+ competes with Ca2+ for binding to troponin — muscle contraction is impaired. This is a key fatigue mechanism.
- Cross-bridge cycle inhibition: The rate of actin-myosin interaction decreases — the ability to generate force decreases.
📊 Increasing Buffer Capacity
| Method | Mechanism | Effectiveness |
|---|---|---|
| Beta-alanine supplements | Increases muscle carnosine content — an intracellular buffer | Proven: a 4-6 week course (3-6 g/d.) can improve performance in exercise lasting 1-7 min. |
| Sodium bicarbonate (NaHCO3) | Increases extracellular bicarbonate content in the blood | Proven: 0.3 g/kg (20 g) before exercise. Effective for 1-10 min. maximal-intensity work |
| Sodium citrate | Alternative to bicarbonate — fewer GI side effects | Less effective than bicarbonate, but better tolerated |
| Dietary nitrates (beetroot juice) | Reduces O2 consumption, indirectly reduces anaerobic glycolysis | 2-3% improvement in endurance. Effect via NO→mitochondria, not via buffers |
⚠️ Practical Recommendations
The use of buffer supplements must be individualized and tested in training before competition. Sodium bicarbonate can cause GI discomfort — start with small doses (0.1-0.2 g/kg) and increase gradually. Beta-alanine causes a "tingling" sensation (paresthesia) — this is harmless but may be unpleasant. Use extended-release formulas or divide the dose into smaller portions.
🙋 Frequently Asked Questions
Yes! Understanding acid-base balance in sport helps you train more effectively, avoid injuries and achieve better results even at amateur level.
We recommend PubMed, Google Scholar, and Sports Medicine journals. It is also worth following publications from the Lithuanian Sports University.
It depends on the specific study. Some methods require laboratory equipment, while others can be performed with portable devices.
Coaches who understand acid-base balance in sport can individualize training programs, monitor progress and adjust loads in time.
📚 Additional Resources and Sources
To deepen your knowledge of acid-base balance in sport, we recommend:
- Scientific publications and conferences of the Lithuanian Sports University (LSU)
- International journals: Journal of Sports Sciences, Medicine and Science in Sports and Exercise
- Annual congresses of the European College of Sport Science (ECSS)
- Sports science podcasts: Science of Sport, The Real Science of Sport
- Sports science programs of the Lithuanian National Olympic Committee (LTOK)
⚡ Pro Tip
Sports science is constantly evolving. What was considered true 10 years ago may be refuted today by new research. Be curious, read the latest literature, and don't be afraid to experiment — of course, while following safety principles.