Confounding factors in peripheral thermal recovery time after active cooling

Area of Science:

• Physiology
• Medical Imaging
• Biomedical Engineering

Background:

• Medical thermography aids in diagnosing conditions like peripheral artery disease, but physiological thermoregulation can complicate interpretation.
• Differentiating pathological thermal changes from normal physiological responses is challenging.

Purpose of the Study:

• To investigate potential confounding factors, specifically age and sex, on thermal recovery rate after active limb cooling.
• To assess the influence of age and sex on thermal recovery time constants in healthy individuals.

Main Methods:

• 53 healthy participants (14 male, 39 female) underwent active limb cooling using cold pads.
• Thermal recovery time was measured using two thermal cameras on the lower limbs (plantar and dorsal sides).
• Recovery time was determined by fitting an exponential curve to the temperature data until a stable level was reached.

Main Results:

• A low to moderate linear correlation was observed between thermal recovery time constant and age, particularly in medial regions.
• No statistically significant differences in thermal recovery time or temperature differences were found between male and female participants.
• Participant's body mass, BMI, and systolic blood pressure showed low or no correlation with thermal recovery time.

Conclusions:

• Thermal recovery time constant after active cooling is largely independent of most tested confounding factors, with age being a notable exception.
• Age must be considered when interpreting thermal recovery measurements in dynamic thermal imaging.
• Further research into dynamic thermal imaging methodologies is warranted.