Individuals who operate in cold weather are at risk of developing cold injuries, for example, frostbite. They also often experience a loss of hand function and joint mobility due to a decrease in skin temperature and blood flow.

In addition, the risk of getting a cold injury is higher in the Black population compared to other racial and ethnic groups. Increases in oxidant compounds can cause the blood vessels in the skin to narrow and decrease skin temperature in the cold. However, it is unknown whether the higher risk of cold injury in Black individuals is because of a greater amount of oxidant compounds in the blood vessels. The purpose of this research is to see if an antioxidant supplement called MitoQ can help to improve skin temperature and blood flow in the cold and if the improvement is greater in Black individuals.

In a randomized, double-blinded, crossover design, healthy volunteers (18-40 yrs) will undergo a set of cold exposures following acute ingestion of a high-dose MitoQ supplement and placebo. The cold exposures will consist of a hand immersion in 54°F water and a 90-min exposure to 41°F air during which skin blood flow and temperatures will be measured. The hypothesis is that the declines in skin blood flow and temperature will be greater during cold exposure in Black individuals and that MitoQ supplementation will improve skin blood flow and temperature to a greater extent in Black individuals.

Inclusion Criteria:

• Male or female, age 18-40
• 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 antioxidant-rich foods, such as blueberries, pecans, and dark chocolate, 48 h before each testing session
• Eumenorrheic females (menstrual cycle length between 24-35 days) or females taking oral contraceptives, or utilizing implantable contraception (e.g., intrauterine device)
• Have supervisor approval if active-duty military or a federal employee at NSSC

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
• Smoke, vape, or use smokeless tobacco or other nicotine-containing products habitually (unless have quit > 4 months prior)
• Current use of medications (except for birth control) or dietary supplements that could alter cardiovascular, thermoregulatory, or vascular control (e.g., anti-hypertensives, statins)
• History of disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis; or previous gastrointestinal surgery
• Have a history of renal disease including (but not limited to) chronic kidney disease, acute kidney injury, kidney stone disease, glomerular disease, or nephritis
• Known allergies to medical adhesives
• Known allergy to MitoQ
• Difficulty swallowing pills
• Heart, lung, kidney, muscle, or nerve disorder(s)
• A planned MRI during the study or within 3 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)
• Have donated blood within 8 weeks of the study or plan to donate blood during the study
• Lesions on a significant portion of the upper extremities due to skin pigmentation disorders (e.g., vitiligo, psoriasis)