【Research Review】Effects of Heat Acclimation Training on Plasma Volume Expansion and Core Temperature Adaptation in Marathon Runners: Latest Academic Literature Review and Training Practice (Article 1336)

Reference Journal Source: Journal of Applied Physiology • International Research Findings Review Series

This article explores the physiological mechanisms of heat acclimation training on plasma volume expansion and core temperature regulation adaptation in marathon runners.

Physiological Mechanisms of Plasma Volume Expansion

Repeated heat exposure stimulates the kidneys and endocrine system to release antidiuretic hormone and aldosterone, prompting the body to retain more water and sodium ions, thereby expanding plasma volume. After plasma volume increases, under the same cardiac output, skin blood flow and muscle blood flow can both receive more adequate supply simultaneously—this is precisely the key to how heat adaptation improves both “heat dissipation capacity” and “athletic performance”: before plasma volume expansion, the body must compete between “muscle blood supply” and “skin heat-dissipation blood supply”; after adaptation, this competition is greatly alleviated.

Core Temperature Regulation Adaptation Process

The complete heat adaptation process typically requires 10-14 days of repeated exposure. During the adaptation process, the following observations can be made:

• The core temperature threshold for sweat initiation decreases (sweating begins earlier, heat dissipation response becomes more sensitive)
• Sweat rate per unit time increases, but sodium ion concentration in sweat decreases (reducing electrolyte loss)
• At the same exercise intensity, the rise in core temperature is smaller, and resting heart rate decreases

Heat Adaptation Days and Physiological Indicator Changes (Illustrative)

Key Research Conclusions and Practical Recommendations

• Exposure Methods: Can be achieved through actual hot-environment training, or by arranging additional hot baths/sauna passive heat exposure after training in a mild environment to accelerate adaptation
• Electrolyte Supplementation: Sweat rate increases substantially during the adaptation period; sodium and fluid intake frequency should be increased to avoid the risk of hyponatremia
• Progressive Approach: Early heat adaptation training should reduce exercise intensity to avoid the risk of heat stroke from simultaneously spiking core temperature and cardiovascular load
• Adaptation Fades: Heat adaptation effects gradually diminish approximately 1-3 weeks after cessation of exposure; pre-race heat adaptation schedules should complete the main adaptation period within 2 weeks before the race

Common Research Q&A (FAQ)

Q: Is heat acclimation training suitable for all marathon runners?

A: The benefits are most pronounced for runners expected to compete in hot, humid environments. If the race location has a cool climate, the marginal benefit of heat adaptation decreases, but plasma volume expansion itself still has positive effects on general endurance performance.

Q: Can sauna use replace actual heat training?

A: It can serve as a supplementary method—passive heat exposure can indeed induce some adaptive responses, but it cannot fully replace the training-specific adaptation that occurs when “exercise + heat” happen simultaneously. It is recommended to combine both approaches.

References and Academic Citations

1. Journal of Applied Physiology — Research directions related to heat adaptation and plasma volume regulation mechanisms.
2. Scandinavian Journal of Medicine & Science in Sports — Literature related to the effects of heat acclimation training interventions in endurance athletes.

Related Topic Reading

• 【Research Review】Effects of Heat Acclimation Training on Plasma Volume Expansion and Core Temperature Adaptation in Marathon Runners: Latest Academic Literature Review and Training Practice (Article 1369)
• 【Research Review】Effects of Heat Acclimation Training on Plasma Volume Expansion and Core Temperature Adaptation in Marathon Runners: Latest Academic Literature Review and Training Practice (Article 478)
• 【Research Review】Effects of Heat Acclimation Training on Plasma Volume Expansion and Core Temperature Adaptation in Marathon Runners: International Research Literature Compilation and Review Report (Article 652)
• 【Research Review】Effects of Heat Acclimation Training on Plasma Volume Expansion and Core Temperature Adaptation in Marathon Runners: International Research Literature Compilation and Review Report (Article 751)