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

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)