Understanding Perspiration: How Sweating Regulates Body Temperature

Perspiration (sweating) is the primary mechanism for human thermoregulation.

Mechanism

• Hypothalamus detects core temperature rise.
• Sympathetic cholinergic fibers stimulate eccrine sweat glands.
• Sweat (water + electrolytes + trace urea/lactate) secreted onto skin.
• Evaporation removes latent heat (~580 kcal/L) → cools blood in dermal capillaries → lowers core temperature.

Influencing Factors

• Environmental temperature/humidity (high humidity impairs evaporation).
• Exercise intensity.
• Emotional stress (sympathetic activation).
• Acclimatization (heat-trained individuals sweat earlier, more dilute).
• Individual variation (genetics, fitness, body composition).

Physiological Roles Beyond Cooling

• Electrolyte balance (Na⁺, Cl⁻ loss; aldosterone conserves).
• Excretion of trace metals, drugs.
• Skin hydration, antimicrobial peptides (dermcidin).

Clinical Note

Excessive (hyperhidrosis) or absent (anhidrosis) sweating may indicate medical conditions (thyroid, autonomic neuropathy, medications).