Key Takeaway
Cooling the palms (glabrous skin) is as effective as whole-body cooling for reducing core temperature due to specialized blood vessel structures.
Summary
This foundational paper by Stanford researchers Heller and Grahn explains why palm cooling works so well. The palms, soles, and face contain specialized blood vessels called arteriovenous anastomoses (AVAs) that allow direct arterial-to-venous blood flow.
When these AVA-rich areas are cooled, blood bypasses the capillary beds and flows rapidly back to the core, efficiently transferring heat out of the body. This makes palm cooling nearly as effective as whole-body cooling for reducing core temperature.
The paper establishes the scientific foundation for using palm cooling in athletic, military, and clinical applications.
Methods
- Review of thermoregulatory mechanisms
- Explanation of AVA physiology
- Comparison of cooling methods
- Discussion of practical applications
Key Results
- Glabrous skin (palms, soles, face) contains AVAs
- AVAs allow rapid heat transfer from core to surface
- Palm cooling can reduce core temp as effectively as whole-body methods
- Critical temperature range: too cold causes vasoconstriction
Limitations
- Primarily a review/theory paper
- Optimal protocols not established in this paper
- Individual variation in AVA density not addressed