Nitrate ingestion blunts the increase in blood pressure during cool air exposure: a double-blind, placebo-controlled, randomized, crossover trial.

Cold exposure increases blood pressure (BP) and salivary flow rate (SFR). Increased cold-induced SFR would be hypothesized to enhance oral nitrate delivery for reduction to nitrite by oral anaerobes and to subsequently elevate plasma [nitrite] and nitric oxide bioavailability. We tested the hypothesis that dietary nitrate supplementation would increase plasma [nitrite] and lower BP to a greater extent in cool compared with normothermic conditions.

Plasma biomarkers of endothelial function, inflammation and oxidative stress in individuals with non-freezing cold injury.

New Findings: What is the central question of this study? Are biomarkers of endothelial function, oxidative stress and inflammation altered by non-freezing cold injury (NFCI)? What is the main finding and its importance? Baseline plasma [interleukin-10] and [syndecan-1] were elevated in individuals with NFCI and cold-exposed control participants. Increased [endothelin-1] following thermal challenges might explain, in part, the increased pain/discomfort experienced with NFCI. Mild to moderate chronic NFCI does not appear to be associated with either oxidative stress or a pro-inflammatory state.

The peripheral vascular responses in non-freezing cold injury and matched controls.

New Findings: What is the central question of this study? Does non-freezing cold injury (NFCI) alter normal peripheral vascular function? What is the main finding and its importance? Individuals with NFCI were more cold sensitive (rewarmed more slowly and felt more discomfort) than controls. Vascular tests indicated that extremity endothelial function was preserved with NFCI and that sympathetic vasoconstrictor response might be reduced. The pathophysiology underpinning the cold sensitivity associated with NFCI thus remains to be identified.

ACSM Expert Consensus Statement: Injury Prevention and Exercise Performance during Cold-Weather Exercise.

Cold injury can result from exercising at low temperatures and can impair exercise performance or cause lifelong debility or death. This consensus statement provides up-to-date information on the pathogenesis, nature, impacts, prevention, and treatment of the most common cold injuries.

Infrared cameras overestimate skin temperature during rewarming from cold exposure.

Objective: The primary aim of this study was to assess the accuracy of an infrared camera and that of a skin thermistor, both commercially available. The study aimed to assess the agreement over a wide range of skin temperatures following cold exposure.

Methods: Fifty-two males placed their right hand in a thin plastic bag and immersed it in 8 °C water for 30 min whilst seated in an air temperature of 30 °C.

Previous recreational cold exposure does not alter endothelial function or sensory thermal thresholds in the hands or feet.

New Findings: What is the central question of this study? Does recreational cold exposure result in cold sensitivity and is this associated with endothelial dysfunction and impaired sensory thermal thresholds? What is the main finding and its importance? Previous cold exposure was correlated with cold sensitivity of the foot, which might indicate the development of a subclinical non-freezing cold injury. Endothelial function and thermal detection were not impaired in cold-sensitive individuals; therefore, further research is required to understand the pathophysiology of subclinical and clinical forms of non-freezing cold injury.

Abstract: In this study, we investigated whether cold-sensitive (CS) individuals, who rewarm more slowly after a mild cold challenge, have impaired endothelial function and sensory thermal thresholds (STTs) and whether this is related to reported cold exposure.

"Beet" the cold: beetroot juice supplementation improves peripheral blood flow, endothelial function, and anti-inflammatory status in individuals with Raynaud's phenomenon.

Raynaud's phenomenon (RP) is characterized by recurrent transient peripheral vasospasm and lower nitric oxide (NO) bioavailability in the cold. We investigated the effect of nitrate-rich beetroot juice (BJ) supplementation on ) NO-mediated vasodilation, ) cutaneous vascular conductance (CVC) and skin temperature (T) following local cooling, and ) systemic anti-inflammatory status. Following baseline testing, 23 individuals with RP attended four times, in a double-blind, randomized crossover design, following acute and chronic (14 days) BJ and nitrate-depleted beetroot juice (NDBJ) supplementation.

Effects of dietary nitrate supplementation on the response to extremity cooling and endothelial function in individuals with cold sensitivity. A double blind, placebo controlled, crossover, randomised control trial.

Individuals with cold sensitivity have low peripheral skin blood flow and skin temperature possibly due to reduced nitric oxide (NO•) bioavailability. Beetroot has a high concentration of inorganic nitrate and may increase NO-mediated vasodilation. Using a placebo-controlled, double blind, randomised, crossover design, this study tested the hypotheses that acute beetroot supplementation would increase the rate of cutaneous rewarming following a local cold challenge and augment endothelium-dependent vasodilation in cold sensitive individuals.

Role of cyclooxygenase in the vascular responses to extremity cooling in Caucasian and African males.

What is the central question of this study? Compared with Caucasians, African individuals are more susceptible to non-freezing cold injury and experience greater cutaneous vasoconstriction and cooler finger skin temperatures upon hand cooling. We investigated whether the enzyme cyclooxygenase is, in part, responsible for the exaggerated response to local cooling. What is the main finding and its importance? During local hand cooling, individuals of African descent experienced significantly lower finger skin blood flow and skin temperature compared with Caucasians irrespective of cyclooxygenase inhibition.

Role of cyclooxygenase in the vascular response to locally delivered acetylcholine in Caucasian and African descent individuals.

Introduction: Individuals of African descent (AFD) are more susceptible to non-freezing cold injury (NFCI) compared with Caucasian individuals (CAU). Vasodilatation to acetylcholine (ACh) is lower in AFD compared with CAU in the non-glabrous foot and finger skin sites; the reason for this is unknown. Prostanoids are responsible, in part, for the vasodilator response to ACh, however it is not known whether the contribution differs between ethnicities.

Swim performance and thermoregulatory effects of wearing clothing in a simulated cold-water survival situation.

Purpose: Accidental cold-water immersion (CWI) impairs swim performance, increases drowning risk and often occurs whilst clothed. The impact of clothing on thermoregulation and swim performance during CWI was explored with the view of making recommendations on whether swimming is viable for self-rescue; contrary to the traditional recommendations.

Method: Ten unhabituated males (age 24 (4) years; height 1.

Vascular responses of the extremities to transdermal application of vasoactive agents in Caucasian and African descent individuals.

Purpose: Individuals of African descent (AFD) are more susceptible to non-freezing cold injury than Caucasians (CAU) which may be due, in part, to differences in the control of skin blood flow. We investigated the skin blood flow responses to transdermal application of vasoactive agents.

Methods: Twenty-four young males (12 CAU and 12 AFD) undertook three tests in which iontophoresis was used to apply acetylcholine (ACh 1 w/v %), sodium nitroprusside (SNP 0.

The effect of ethnicity on the vascular responses to cold exposure of the extremities.

Purpose: Cold injuries are more prevalent in individuals of African descent (AFD). Therefore, we investigated the effect of extremity cooling on skin blood flow (SkBF) and temperature (T sk) between ethnic groups.

Methods: Thirty males [10 Caucasian (CAU), 10 Asian (ASN), 10 AFD] undertook three tests in 30 °C air whilst digit T sk and SkBF were measured: (i) vasomotor threshold (VT) test--arm immersed in 35 °C water progressively cooled to 10 °C and rewarmed to 35 °C to identify vasoconstriction and vasodilatation; (ii) cold-induced vasodilatation (CIVD) test--hand immersed in 8 °C water for 30 min followed by spontaneous warming; (iii) cold sensitivity (CS) test--foot immersed in 15 °C water for 2 min followed by spontaneous warming.

Habituation of the metabolic and ventilatory responses to cold-water immersion in humans.

An experiment was undertaken to answer long-standing questions concerning the nature of metabolic habituation in repeatedly cooled humans. It was hypothesised that repeated skin and deep-body cooling would produce such a habituation that would be specific to the magnitude of the cooling experienced, and that skin cooling alone would dampen the cold-shock but not the metabolic response to cold-water immersion. Twenty-one male participants were divided into three groups, each of which completed two experimental immersions in 12°C water, lasting until either rectal temperature fell to 35°C or 90min had elapsed.

Cold sensitivity test for individuals with non-freezing cold injury: the effect of prior exercise.

Background: One of the chronic symptoms of non-freezing cold injury (NFCI) is cold sensitivity. This study examined the effects of prior exercise on the response to a cold sensitivity test (CST) in NFCI patients with the aim of improving diagnostic accuracy.

Methods: Twenty three participants, previously diagnosed with NFCI by a Cold Injuries Clinic, undertook two CSTs.

Can firefighter instructors perform a simulated rescue after a live fire training exercise?

Two studies were undertaken to determine whether firefighter instructors are capable of performing a simulated rescue task after undertaking a live fire training exercise (LFTE) lasting approximately 40 min. In the first study, ten instructors performed two simulated rescue tasks in air at 19 degrees C, involving dragging an 81-kg dummy for 15 m along a corridor and down two flights of stairs. The first rescue acted as a control (Rcontrol) and was conducted when they were euhydrated and normothermic.

Repeated cold showers as a method of habituating humans to the initial responses to cold water immersion.

The hypothesis that the initial responses to cold water immersion could be attenuated by repeated cold showers was tested. Eighteen (13 men, 5 women) non-habituated subjects undertook two 3-min head-out seated immersions into stirred water at 10 degrees C wearing swim wear. The immersions were separated by 4 days during which time they took six cold showers.

Physiological responses of fire-fighter instructors during training exercises.

Thirteen male instructors were monitored during a total of 44 live fire training exercises (ambient temperature 74+/-42 degrees C). Exposure time during the 'Hot Fire' (HF), 'Fire Behaviour' and 'Fire Attack' exercises was 33.0+/-7.