The Effects of Cold Adaptation on Skin Blood Flow, Hand Function, and Comfort in Healthy Adults

Participants (n=15, 18-39 yrs) will complete a preliminary cold air exposure (baseline testing) followed by 8 days of repeated cold air exposures with minimal clothing. The cold exposures will be 2 hours in duration and will be conducted in 8°C (46°F) conditions. Before and after the repeated cold exposures, participants will undergo hand function tests, assessments of thermal comfort, and skin blood flow testing.

Inclusion criteria

• Male or female, age 18-39
• In good health as determined by OMSO (Office of Medical Support and Oversight)
• Willing to refrain from exercise and caffeinated or alcoholic beverages for 12 hours before each testing session
• Willing to refrain from smoking or tobacco use 8 hours before each testing session

Exclusion criteria

• History of cold injuries of any severity (e.g., frostbite, trench foot, chilblains).
• Raynaud's syndrome.
• Cold-induced asthma/bronchospasm
• Previous hand/finger injuries that impair dexterity and hand function.
• Metal hardware (plates/screws) in the forearms and hands.
• Current use of medications or dietary supplements that could alter cardiovascular, thermoregulatory, or vascular control (e.g., anti-hypertensives, statins).
• Known allergies to medical adhesives.
• Heart, lung, kidney, muscle, or nerve disorder(s)
• A planned MRI during the study or within 2 days after completing a cold test.
• Women who are pregnant, planning to become pregnant, or breastfeeding.
• Not willing to have small areas of skin on the body shaved (if deemed necessary for attachment of study instrumentation)