The Unique Demands of Endurance Sport
Endurance sport — running, cycling, cross-country skiing, swimming — requires the body to work at sustained high intensity. This creates unique nutritional needs that regular training does not: increased iron losses, intense sweating, high energy demands, and the need for faster recovery.
Estonia's active endurance community — the Tallinn Marathon, Tartu Marathon, cycling marathons — knows that performance can be optimised with smartly chosen supplements.
Essential Supplements for Endurance Athletes
1. Iron — Non-Negotiable for Endurance
Iron contributes to normal formation of red blood cells and haemoglobin and to normal oxygen transport in the body. Endurance athletes face a higher risk of iron deficiency, especially runners (mechanical haemolysis from foot-strike impact).
- Recommended dose: 14-18 mg per day (only with confirmed deficiency, under medical supervision)
- Deficiency symptoms: Unexplained fatigue, declining performance, rapid heart rate
- Important: Check ferritin levels at least twice a year. Do not supplement iron without a blood test.
- Tip: Take with vitamin C for better absorption. Avoid coffee and tea within 1 hour
2. Electrolytes
Electrolytes are critical during prolonged efforts. Sodium, potassium, and magnesium are lost through sweat.
- Sodium: 500-1,000 mg/h during long sessions (over 90 minutes)
- Potassium: 200-400 mg/h
- Usage: Start consuming electrolytes before you feel thirsty
3. Caffeine — A Proven Ergogenic Aid
Caffeine is one of the most researched and effective sports supplements. It can help improve endurance and reduce perceived exertion.
- Recommended dose: 3-6 mg per kg of body weight, 30-60 minutes before performance (Ganio et al., 2009)
- Example: For a 70 kg athlete = 210-420 mg caffeine
- Form: Caffeine tablets, caffeine gels, or coffee
- Warning: Practise before competition. Never try for the first time on race day
4. Beetroot Extract (Nitrate)
Nitrates from beetroot juice are converted in the body to nitric oxide, which dilates blood vessels and improves oxygen delivery to working muscles.
- Recommended dose: 300-500 ml beetroot juice (6.4-12.8 mmol nitrate) 2-3 hours before performance
- Alternative: Concentrated beetroot shots (compressed dose)
- Tip: Regular consumption for 3-6 days before competition increases the effect
5. Beta-Alanine
Beta-alanine increases carnosine levels in muscles, which helps buffer acidity during more intense efforts (lasting 1-10 minutes).
- Recommended dose: 3.2-6.4 g per day, divided into smaller doses
- Loading period: 4-6 weeks of regular use
- Side effect: Skin tingling (paraesthesia) is safe and temporary
6. Omega-3 Fatty Acids
EPA and DHA contribute to normal heart function. For endurance athletes, heart health is especially important.
- Recommended dose: 1,000-2,000 mg EPA+DHA per day
- Additional benefit: Supports normal joint function under high load
7. Vitamin D
Vitamin D contributes to normal muscle function and to the maintenance of normal bones. In the Estonian climate, the risk of deficiency is high, especially during the winter training period.
- Recommended dose: 2,000-4,000 IU per day (in winter)
Supplement Periodisation Across Training Blocks
Base Training (Low Intensity, High Volume)
- Focus: Iron, omega-3, vitamin D, magnesium
- Caffeine: Minimal use (keep tolerance low)
Build Phase (Increasing Intensity)
- Focus: Add beetroot nitrate, increase electrolytes
- Caffeine: Use only for key sessions
Competition Phase
- Focus: Caffeine, beetroot nitrate, electrolytes
- Iron: Check levels before competition
Recovery Phase
- Focus: Omega-3, magnesium, protein
- Reduce stimulant use
Common Mistakes
- Iron supplementation without testing — excess iron is dangerous. Always check ferritin first.
- Caffeine overconsumption — regular high intake builds tolerance. Cycling on and off is more effective.
- Ignoring electrolytes during training — water alone is not enough for prolonged efforts.
- Trying new supplements on race day — always test during training first.
Frequently Asked Questions
Does caffeine dehydrate you? At moderate doses (3-6 mg/kg), caffeine does not cause significant dehydration during exercise.
Do I need to take beta-alanine every day? Yes, beta-alanine works on a cumulative basis. Regular daily intake over 4-6 weeks increases carnosine levels.
Is creatine suitable for endurance athletes? Creatine is traditionally associated with strength sports, but endurance athletes can also benefit from improved interval training quality.
See Also
Browse our supplement selection →
References
- Ganio, M.S. et al. (2009). Effect of caffeine on sport-specific endurance performance: a systematic review. Journal of Strength and Conditioning Research, 23(1), 315-324.
- Thomas, D.T., Erdman, K.A. & Burke, L.M. (2016). Position of the Academy of Nutrition and Dietetics: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501-528.
- Peeling, P. et al. (2008). Athletic induced iron deficiency: new insights into the role of inflammation, cytokines and hormones. European Journal of Applied Physiology, 103(4), 381-391.
- Dominguez, R. et al. (2017). Effects of beetroot juice supplementation on cardiorespiratory endurance in athletes: a systematic review. Nutrients, 9(1), 43.
Disclaimer
A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.
