Wet military uniforms pose low risk of hypothermia while static in mild cold air.

Wet clothing is less insulative than dry clothing and consequently increases heat loss in cold air. Tactical necessity can render removal of wet clothing impossible and/or require Warfighters to remain static to avoid detection, limiting heat production and posing a threat of hypothermia (core temperature <35 °C). This study aimed to characterize body temperatures and evaluate hypothermia risk while statically exposed to 5 °C air wearing three wet military uniforms.

Short-term cocoa bioflavanol supplementation does not improve cold-induced vasodilation in young healthy adults.

Purpose: Cold-induced vasodilation (CIVD) is an oscillatory rise in blood flow to glabrous skin that occurs in cold-exposed extremities. Dietary flavanols increase bioavailable nitric oxide, a proposed mediator of CIVD through active vasodilation and/or withdrawal of sympathetic vascular smooth muscle tone. However, no studies have examined the effects of flavanol intake on extremity skin perfusion during cold exposure.

Sex differences in thermal sensitivity and perception: Implications for behavioral and autonomic thermoregulation.

Temperature sensitive receptors in the skin and deep body enable the detection of the external and internal environment, including the perception of thermal stimuli. Changes in heat balance require autonomic (e.g.

Influences of ovarian hormones on physiological responses to cold in women.

While it is clear that the ovarian hormones estradiol and progesterone have important influences on physiological thermoregulation in women, the influences of these hormones on responses to cold exposure are not well understood. Both heat conservation and heat production must increase to offset heat losses that decrease body temperature in cold ambient conditions. Cutaneous vasoconstriction conserves heat, whereas shivering and non-shivering thermogenesis produce heat - all as part of reflex physiological responses to cold exposure.

Human cold habituation: Physiology, timeline, and modifiers.

Habituation is an adaptation seen in many organisms, defined by a reduction in the response to repeated stimuli. Evolutionarily, habituation is thought to benefit the organism by allowing conservation of metabolic resources otherwise spent on sub-lethal provocations including repeated cold exposure. Hypermetabolic and/or insulative adaptations may occur after prolonged and severe cold exposures, resulting in enhanced cold defense mechanisms such as increased thermogenesis and peripheral vasoconstriction, respectively.

Effect of 8 days of exercise-heat acclimation on aerobic exercise performance of men in hypobaric hypoxia.

Exercise-heat acclimation (EHA) induces adaptations that improve tolerance to heat exposure. Whether adaptations from EHA can also alter responses to hypobaric hypoxia (HH) conditions remains unclear. This study assessed whether EHA can alter time-trial performance and/or incidence of acute mountain sickness (AMS) during HH exposure.

Influence of Acetazolamide on Hand Strength and Manual Dexterity During a 30-h Simulated High Altitude Exposure.

Introduction: High altitude missions pose significant challenges to Warfighter medical readiness and performance. Decreased circulating oxygen levels cause a decrease in exercise performance and can cause debilitating symptoms associated with acute mountain sickness, especially with rapid ascent. Acetazolamide (AZ) is known to minimize symptoms of acute mountain sickness, but it is unknown whether this medication alters hand strength and manual dexterity during altitude exposure.

Controlled Feeding of an 8-d, High-Dairy Cheese Diet Prevents Sodium-Induced Endothelial Dysfunction in the Cutaneous Microcirculation of Healthy, Older Adults through Reductions in Superoxide.

Background: While excess dietary sodium impairs vascular function by increasing oxidative stress, the dietary incorporation of dairy foods improves vascular health. We demonstrated that single-meal cheese consumption ameliorates acute, sodium-induced endothelial dysfunction. However, controlled feeding studies examining the inclusion of cheese, a dairy product that contains both bioactive constituents and sodium, are lacking.

Cold-induced cutaneous vasoconstriction in humans: Function, dysfunction and the distinctly counterproductive.

New Findings: What is the topic of this review? This review presents an update and synthesis of normal mechanisms of human cutaneous vasoconstriction in response to cold stress. It then discusses conditions in which cutaneous vasoconstrictor responses are excessive or insufficient and cases in which cold-induced vasoconstrictor responses become counter to maintaining thermal and haemodynamic homeostasis. What advances does it highlight? The review highlights our current understanding of the mechanisms that mediate alterations in cold-induced cutaneous vasoconstriction in pathology and environmental extremes, which has important clinical implications for preventing cold- and cardiovascular-related deaths.

Endothelial function is impaired in the cutaneous microcirculation of adults with psoriasis through reductions in nitric oxide-dependent vasodilation.

Psoriasis is an independent risk factor for cardiovascular disease; however, the underlying mechanisms are not fully understood. Deficits in conduit arterial function are evident in patients with psoriasis, but potential impairments in microcirculatory endothelial function remain unclear. We hypothesized that cutaneous microvascular dysfunction would be detectable in otherwise healthy individuals with psoriasis.

Dairy cheese consumption ameliorates single-meal sodium-induced cutaneous microvascular dysfunction by reducing ascorbate-sensitive oxidants in healthy older adults.

Chronic dairy product intake is associated with improved cardiovascular outcomes, whereas high dietary Na impairs endothelial function through increased oxidative stress and reduced nitric oxide (NO) bioavailability. The purpose of this study was to compare the effect of acute cheese consumption with consumption of Na from non-dairy sources on microvascular function. We hypothesised that dairy cheese ingestion would augment NO-dependent vasodilation compared with Na from non-dairy sources.

Acute dairy milk ingestion does not improve nitric oxide-dependent vasodilation in the cutaneous microcirculation.

In epidemiological studies, chronic dairy milk consumption is associated with improved vascular health and reduced age-related increases in blood pressure. Although milk protein supplementation augments conduit artery flow-mediated dilation, whether or not acute dairy milk intake may improve microvascular function remains unclear. We hypothesised that dairy milk would increase direct measurement of endothelial nitric oxide (NO)-dependent cutaneous vasodilation in response to local skin heating.