Separate and combined blockades of α- and β-adrenergic receptors in forearm sweating induced by adrenergic agents and exercise in the heat in young adults.

The assessment of adrenergic modulation of sweating as assessed via pharmacologic administration of α- and β-adrenergic receptor blockers during exercise has yielded mixed findings. However, the underlying mechanisms for this disparity remains unresolved. We investigated the effects of separate and combined blockade of α- and β-adrenergic receptors on forearm sweating induced by a 30-min moderate-intensity exercise bout (n=17, protocol 1) and the administration of adrenergic agonists epinephrine and norepinephrine (n=16, protocol 2) in the heat.

In vivo assessments of microneedle arrays and iontophoresis of pilocarpine in human palmar sweating.

Emotional stress-induced sweating in glabrous skin of the palm and sole, which can be excessive in some individuals (hyperhidrosis), can negatively impact quality of life. Understanding the mechanisms underlying this response can lead to potential treatments. Transdermal iontophoresis is a method to administer ionized sudorific agents to sweat glands within the dermis.

Induction and decay of seasonal acclimatization on whole body heat loss responses during exercise in a hot humid environment with different air velocities.

Whether whole body heat loss and thermoregulatory function (local sweat rate and skin blood flow) are different between summer and autumn and between autumn and winter seasons during exercise with different air flow in humid heat remain unknown. We therefore tested the hypotheses that whole body sweat rate (WBSR), evaporated sweat rate, and thermoregulatory function during cycling exercise in autumn would be higher than in winter but would be lower than in summer under hot-humid environment (32 C, 75% RH). We also tested the hypothesis that the increase of air velocity would enhance evaporated sweat rate and sweating efficiency across winter, summer, and autumn seasons.

Effects of tetraethylammonium-sensitive K channel blockade on cholinergic and thermal sweating in endurance-trained and untrained men.

New Findings: What is the central question of this study? Does inhibition of K channels modulate the exercise-training-induced augmentation in cholinergic and thermal sweating? What is the main finding and its importance? Iontophoretic administration of tetraethylammonium, a K channel blocker, blunted sweating induced by a low dose (0.001%) of the cholinergic agent pilocarpine, but not heat-induced sweating. However, no differences in the cholinergic sweating were observed between young endurance-trained and untrained men.

Influence of exercise intensity and regional differences in the sudomotor recruitment pattern in exercising prepubertal boys and young men.

We investigated the influence of exercise intensities and regional differences in the sudomotor recruitment pattern in boys. Six prepubertal boys (age 11 ± 1 yr) cycled at light, moderate, and high exercise intensity (35%, 50%, and 65% VOmax) for 30 min in a temperate condition (28 °C, 40% relative humidity). Local sweat rate (ventilated capsule) and number of activated sweat glands (starch-iodine technique) at five body sites were assessed and sweat gland output was calculated.

The effect of seasonal acclimatization on whole body heat loss response during exercise in a hot humid environment with different air velocity.

Seasonal acclimatization from winter to summer is known to enhance thermoeffector responses in hot-dry environments during exercise whereas its impact on sweat evaporation and core temperature (T) responses in hot-humid environments remains unknown. We, therefore, sought to determine whether seasonal acclimatization is able to modulate whole body sweat rate (WBSR), evaporated sweat rate, sweating efficiency, and thermoregulatory function during cycling exercise in a hot-humid environment (32°C, 75% RH). We also determined whether the increase in air velocity could enhance evaporated sweat rate and sweating efficiency before and after seasonal acclimatization.

Physical activities and surgical outcomes in elderly patients with acute type A aortic dissection.

Objective: Although elderly patients undergoing surgery for acute type A aortic dissection (ATAAD) is increasing, their physical activities are not fully understood. We report the physical activities and surgical outcomes in elderly patients who underwent ATAAD.

Methods: From 2009 to 2019, 103 consecutive patients underwent surgery for ATAAD at our institution.

The relative contribution of α- and β-adrenergic sweating during heat exposure and the influence of sex and training status.

While human eccrine sweat glands respond to adrenergic agonists, there remains a paucity of information on the factors modulating this response. Thus, we assessed the relative contribution of α- and β-adrenergic sweating during a heat exposure and as a function of individual factors of sex and training status. α- and β-adrenergic sweating was assessed in forty-eight healthy young men (n = 35) and women (n = 13) including endurance-trained (n = 12) and untrained men (n = 12) under non-heat exposure (temperate, 25°C; n = 17) and heat exposure (hot, 35°C; n = 48) conditions using transdermal iontophoresis of phenylephrine (α-adrenergic agonist) and salbutamol (β-adrenergic agonist) on the ventral forearm, respectively.

The sweat glands' maximum ion reabsorption rates following heat acclimation in healthy older adults.

New Findings: What is the central question to this study? Do the sweat glands' maximum ion reabsorption rates increase following heat acclimation in healthy older individuals and is this associated with elevated aldosterone concentrations? What is the main finding and its importance? Sweat gland maximum ion reabsorption rates improved heterogeneously across body sites, which occurred without any changes in aldosterone concentration following a controlled hyperthermic heat acclimation protocol in healthy older individuals.

Abstract: We examined whether the eccrine sweat glands' ion reabsorption rates improved following heat acclimation (HA) in older individuals. Ten healthy older adults (>65 years) completed a controlled hyperthermic (+0.

Effects of L-type voltage-gated Ca channel blockade on cholinergic and thermal sweating in habitually trained and untrained men.

We evaluated the hypothesis that the activation of L-type voltage-gated Ca channels contributes to exercise training-induced augmentation in cholinergic sweating. On separate days, 10 habitually trained and 10 untrained men participated in two experimental protocols. Prior to each protocol, we administered 1% verapamil (Verapamil, L-type voltage-gated Ca channel blocker) and saline (Control) at forearm skin sites on both arms via transdermal iontophoresis.

Does the iontophoretic application of bretylium tosylate modulate sweating during exercise in the heat in habitually trained and untrained men?

New Findings: What is the central question of this study? Does the administration of the adrenergic presynaptic release inhibitor bretylium tosylate modulate sweating during exercise in the heat, and does this response differ between habitually trained and untrained men? What is the main finding and its importance? Iontophoretic administration of bretylium tosylate attenuates sweating during exercise in the heat in habitually trained and untrained men. However, a greater reduction occurred in trained men. The findings demonstrate a role for cutaneous adrenergic nerves in the regulation of eccrine sweating during exercise in the heat and highlight a need to advance our understanding of neural control of human eccrine sweat gland activity.

Does α-adrenergic receptor blockade modulate sweating during incremental exercise in young endurance-trained men?

Purpose: Human eccrine sweat glands respond to α-adrenergic receptor agonists. We recently reported that adrenergic mechanisms contribute to sweating in endurance-trained men during an incremental exercise to volitional fatigue. However, it remains unclear if this response is mediated by α-adrenergic receptor activation.

Effects of isomaltulose ingestion on postexercise hydration state and heat loss responses in young men.

New Findings: What is the central question of this study? What are the effects of isomaltulose, an ingredient in carbohydrate-electrolyte beverages to maintain glycaemia and attenuate the risk of dehydration during exercise heat stress, on postexercise rehydration and physiological heat loss responses? What is the main finding and its importance? Consumption of a 6.5% isomaltulose-electrolyte beverage following exercise heat stress restored hydration following a 2 h recovery as compared to a 2% solution or water only. While the 6.

β-Adrenergic receptor blockade does not modify non-thermal sweating during static exercise and following muscle ischemia in habitually trained individuals.

Purpose: This study investigated the influence of β-adrenergic receptor blockade on sweating during bilateral static knee extension (KE) and lateral isometric handgrip (IH) exercises followed by post-exercise muscle ischemia (PEMI) in habitually trained individuals.

Method: Ten habitually trained men (maximum oxygen uptake, 57.1 ± 3.

Age-related attenuation of conduit artery blood flow response to passive heating differs between the arm and leg.

Purpose: Little is known about why the attenuation of heat loss responses with aging begins in the lower limbs. This study sought to determine whether passive heating causes the age-related decrease and limb-specific difference of blood flow (BF) responses between conduit brachial and femoral arteries, which are related to differences of cutaneous vascular conductance (CVC) between the upper and lower limbs.

Method: In 15 older and 12 younger males, BF in the brachial and femoral arteries was ultrasonically measured and CVC in the forearm and thigh was assessed during lower leg immersion in hot water at 42 °C (ambient temperature: 30 °C, relative humidity: 45%) for 40 min.

Cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise in habitually trained men.

It remains unknown whether cutaneous adrenergic nerves functionally contribute to sweat production during exercise. This study examined whether cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise, specifically in habitually trained individuals. Accordingly, 10 habitually trained and 10 untrained males (V̇o: 56.

The effects of exercise and passive heating on the sweat glands ion reabsorption rates.

The sweat glands maximum ion reabsorption rates were investigated (n = 12, 21.7 ± 3.0 years, 59.

Do nitric oxide synthase and cyclooxygenase contribute to sweating response during passive heating in endurance-trained athletes?

The aim of our study was to determine if habitual endurance training can influence the relative contribution of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the regulation of sweating during a passive heat stress in young adults. Ten trained athletes and nine untrained counterparts were passively heated until oral temperature (as estimated by sublingual temperature, T) increased by 1.5°C above baseline resting.

Evidence for β-adrenergic modulation of sweating during incremental exercise in habitually trained males.

The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control).

Maximum rate of sweat ions reabsorption during exercise with regional differences, sex, and exercise training.

Purpose: It is recently reported that determining sweat rate (SR) threshold for increasing galvanic skin conductance (GSC) would represent a maximum rate of sweat ion reabsorption in sweat glands. We evaluate the maximum rate of sweat ion reabsorption over skin regions, sex, and long-term exercise training by using the threshold analysis in the present study.

Methods: Ten males (2 untrained, 4 sprinters, and 4 distance runners) and 12 females (5 untrained, 4 sprinters, and 3 distance runners) conducted graded cycling exercise for 45 min at low, middle, and high exercise intensities (heart rate 100-110, 120-130, and 140-150 beats/min, respectively) for 10, 15, and 20 min, respectively, at 30 °C and 50% relative humidity.

Sweating responses to isometric hand-grip exercise and forearm muscle metaboreflex in prepubertal children and elderly.

What is the central question of this study? Non-thermal factors (e.g. muscle metaboreflex) contribute to the sweating response during exercise.

Effect of stride frequency on thermoregulatory responses during endurance running in distance runners.

Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15km/h for 60min in a controlled environmental chamber (ambient temperature 27°C and relative humidity 50%), and stride frequency was manipulated.

Sex differences in age-related changes on peripheral warm and cold innocuous thermal sensitivity.

Cutaneous thermal sensitivity to a warm and cold stimulus was compared amongst 12 older (OF, 65.2±1.0year) and 29 younger (YF, 21.

Influence of forearm muscle metaboreceptor activation on sweating and cutaneous vascular responses during dynamic exercise.

We examined whether the sustained activation of metaboreceptor in forearm during cycling exercise can modulate sweating and cutaneous vasodilation. On separate days, 12 young participants performed a 1.5-min isometric handgrip exercise at 40% maximal voluntary contraction followed by 1) 9-min forearm ischemia (Occlusion, to activate metaboreceptor) or 2) no ischemia (Control) in thermoneutral conditions (27°C, 50%) with mean skin temperature clamped at 34°C.