Is creatine supplementation only beneficial for individuals performing strength exercises, or can it also enhance endurance in a generally healthy adult?

Creatine Benefits Beyond Strength Training

No, creatine is not only useful for strength exercises—it provides benefits across multiple exercise modalities including endurance activities with repeated high-intensity surges, cognitive function, and activities of daily living, though its effects are most pronounced during short-duration, high-intensity efforts.

Primary Mechanisms Apply Across Exercise Types

Creatine works by increasing phosphocreatine stores in muscle cells by approximately 20%, which enhances rapid ATP resynthesis during any high-intensity effort, not just traditional strength training 1, 2. This mechanism supports:

• High-intensity repeated sprint performance in any sport requiring powerful, short-duration movements 3, 2
• Enhanced training capacity and chronic adaptations including increased muscle strength, power, and lean body mass 3, 2
• Improved anaerobic work capacity during activities exceeding 3 minutes when they include intensity surges 4

Endurance Exercise Benefits

Creatine supplementation improves endurance performance specifically during activities requiring multiple surges in intensity or end-spurts, which are often race-defining moments 4. The evidence shows:

• Increased time to exhaustion during high-intensity endurance activities due to enhanced anaerobic work capacity 4
• Particular benefit for cross-country skiing, mountain biking, cycling, triathlon, rowing, kayaking, and track cycling where intensity varies 4
• Enhanced glycogen resynthesis and content when co-ingested with carbohydrates, supporting high-intensity aerobic exercise 4
• Lower inflammation and oxidative stress, with potential to increase mitochondrial biogenesis 4

Important caveat: The effects of creatine diminish as continuous exercise duration increases without intensity variations 5. The 1-2 kg body mass increase from water retention may offset benefits in pure weight-bearing endurance activities 2, 4.

Cognitive and Functional Benefits

Beyond athletic performance, creatine provides:

• Brain function support by increasing phosphocreatine stores in cerebral tissue 1, 2
• Improved cognitive processing when experimentally or naturally impaired (sleep deprivation, aging) 6
• Enhanced activities of daily living in older adults, independent of exercise training 6
• Increased bone mineral density when combined with resistance training in older populations 6

Recommended Supplementation Protocol

The protocol remains consistent regardless of exercise type 3, 2:

• Loading phase: 20 g/day divided into four 5g doses for 5-7 days
• Maintenance phase: 3-5 g/day as a single dose for duration of supplementation
• Alternative approach: 2-5 g/day for 28 days avoids body mass increase while remaining effective
• Optimization: Consume with ~50g each of protein and carbohydrates to enhance muscle uptake via insulin stimulation 3, 2

Safety Considerations

Creatine supplementation (3-5 g/day) has an excellent safety profile in healthy individuals 3. Key points:

• Short- and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated 3, 7
• Primary side effect is 1-2 kg body mass increase from water retention or increased protein synthesis 3, 2
• Contraindication: Should be discouraged in living kidney donors during evaluation due to unknown effects on kidney function 3
• Does not impair renal function but affects creatinine generation, potentially falsely suggesting acute kidney injury on creatinine-based GFR measurements 3
• Not effective for improving exercise capacity in COPD patients receiving pulmonary rehabilitation 3

Clinical Application Algorithm

Use creatine supplementation when:

• Any high-intensity, repeated effort activity is performed (strength, sprints, intervals) 3, 2
• Endurance sports involve tactical surges or end-spurts 4
• Cognitive enhancement is desired in aging or sleep-deprived individuals 6
• Improving activities of daily living in older adults 6

Avoid or use cautiously when:

• Patient is a living kidney donor candidate 3
• Pure steady-state endurance without intensity variations is the only goal 5, 4
• Weight gain would be detrimental to performance in weight-bearing activities 4