Process- and controller-adaptations determine the physiological effects of cold acclimation

Area of Science:

• Physiology
• Thermoregulation
• Environmental Adaptation

Background:

• Conflicting experimental results on cold adaptation physiology exist.
• A unified functional concept is needed to explain these diverse outcomes.

Purpose of the Study:

• To explain varied cold adaptation results using a common functional concept.
• To analyze physiological responses through a core/shell thermoregulation model.

Main Methods:

• Utilized a core/shell model of the thermoregulatory system.
• Introduced adaptation as a higher control level.
• Differentiated between 'process adaptation' (heat transfer) and 'controller adaptation' (parameter adjustment).

Main Results:

• Controller adaptation (threshold change) in cold acclimation lowers body temperature via reduced metabolism.
• Process adaptation (improved insulation) leads to a rise in body temperature despite reduced metabolism.
• Combined adaptations can result in no net change in body temperature, depending on their proportion.

Conclusions:

• A unified model explains diverse cold adaptation physiological effects.
• The interplay between process and controller adaptation dictates the final body temperature state.
• Understanding these adaptations is crucial for interpreting cold exposure research.