The Effects of Cold Habituation on Peripheral Blood Flow, Hand Function, and Thermal Comfort
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 16
- 试验地点
- 2
- 主要终点
- Skin blood flow
研究概览
简要总结
In cold weather environments, blood flow to the extremities is significantly reduced, which severely impairs hand function and induces thermal discomfort. Prolonged or repeated cold exposure elicits an adaptive habituation response that is characterized by blunted skin vasoconstriction and thus may be an effective strategy to improve peripheral perfusion, reduce thermal discomfort, and maintain hand function during cold weather military operations. Since mission conditions often involve low ambient temperatures, countermeasures that reduce cold-induced decrements in hand function and thermal comfort are important to enhance Warfighter readiness in cold weather battlefield environments. The goals of this study are to 1) evaluate the effectiveness of cold habituation in improving skin blood flow, hand function, and thermal comfort during cold exposure and 2) identify the mechanisms that contribute to improvements in skin blood flow following habituation.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 39 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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
排除标准
- •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)
结局指标
主要结局
Skin blood flow
时间窗: 8 days
Skin blood flow will be measured using non-invasive laser-Doppler flowmetry probes before and during cold exposure. Output (red blood cell flux) will be divided by mean arterial blood pressure to give an index of cutaneous vascular conductance \[CVC, flux/mmHg\].
Skin temperature
时间窗: 8 days
Skin temperatures \[in °C\] at up to 10 sites on the body will be measured using skin thermistors before and during cold exposure. Hand and foot skin temperatures will also be measured with a thermography imaging camera.
Manual dexterity - Pegboard
时间窗: 3 days
Pegboard scores will be obtained before and during cold exposure. Scores are the number of pegs placed into the boards.
Manual dexterity - Minnesota Rate of Manipulation
时间窗: 3 days
Minnesota Rate of Manipulation dexterity scores will be obtained before and during cold exposure. Scores are the time \[in seconds\] required to move small blocks various distances.
Hand and finger strength
时间窗: 3 days
Pinch and hand strength \[in kg\] will be measured using a pinch meter and grip strength device (dynamometer). Participants will complete three pinch strength tests and one grip strength test before and during cold exposure.
Cold perception
时间窗: 5 days
Ratings of thermal comfort, thermal sensation, and pain perception \[in arbitrary units\] will be assessed using visual analogue scales before and during cold exposure.
次要结局
- Metabolic heat production(5 days)
- Plasma norepinephrine(3 days)
- Heart rate(12 days)
- Body core temperature(5 days)
- Blood pressure(12 days)