Endocrine Abstracts

Aims: Exertional hyperthermia stimulates the hypothalamic-pituitary adrenal axis, increasing the availability of free cortisol in body fluids and opening a window onto physical stress for novel biosensing technologies. This study aimed to determine the impact of prolonged endurance exercise on relationships described for shorter activity bouts, by characterising interactions between salivary indices of glucocorticoid activity, serum total cortisol response and...

Introduction: Exercise in the heat can impose significant physiological strain and may result in incapacity, illness and death from exertional heat stroke (EHS). The adrenocortical response to exercise is known to be amplified with concurrent heat stress, suggesting the potential utility of cortisol measurement in dynamic surveillance for heat intolerance. In laboratory conditions, a standard Heat Tolerance Assessment (HTA) may be used to determine thermal tolerance to exercis...

Background: Heat acclimatisation (HA) describes phenotypic changes (decreased heart rate, HR; lower core body temperature, Tc) resulting from exposure to a hot environment. Heat tolerance with HA may reflect altered adrenocortical and autonomic nervous responses to heat stress, though evidence for sympathetic downregulation is lacking. Methodological limitations to further investigation (e.g. with direct catecholamine measurement) could be overcome by assaying the catecholamin...

Background: Work in a hot environment can cause elevated core body temperature (Tc), circulatory insufficiency and death from Exertional Heat Illness (EHI). Failure to undergo successful heat acclimatisation (HA) is seen in ~5% of otherwise healthy volunteers and may lead to significant EHI, but pathways to severe illness remain poorly understood. Copeptin, a glycopeptide co-secreted with the pituitary hormone arginine vasopressin, reflects osmotic and cardiovascular stress an...

Background: Exertional heat illness (EHI) is an incapacitating and sometimes fatal phenomenon. It is associated with elevated core temperature (Tc), cardiovascular instability and the systemic inflammatory response syndrome. EHI-preventive guidelines recommend maintaining Tc ≤38 °C, an important thermoregulatory threshold above which vasomotor compensation plateaus and pronounced excursions in key pituitary and adrenal hormones occur. Copeptin, the C-terminal part o...

Aims: Type 2 diabetes (T2DM) now affects a significant proportion of young people worldwide. ‘X-borough’ contains a strikingly young, diverse population with one of the highest rates of prevalence for adult T2DM in the UK. Our aims were to determine the prevalence and examine the characteristics of young people with T2DM in this population.Methods: Forty-four young people (<25 years) with T2DM were matched with an equal number of young peop...

Background: Regulation of core body temperature (Tc) can cause significant cardiovascular strain, leading to impaired performance, incapacitation and occupational hazard during work in the heat. Where continuous Tc and heart rate (HR) monitoring is not possible (e.g. during firefighting or on military operations), safer working could result from intermittent sampling of an integrated measure of physiological strain.Aims: To assess the relationship betwee...

We have previously reported that exercise at high altitude (HA) led to a significant increase in brain natriuretic peptide (BNP) levels. In contrast two other publications have reported no change in resting BNP at HA. We therefore measured BNP and Lake Louise (LL) Acute Mountain Sickness (AMS) scores in a further 20 subjects at rest in Kathmandu (Kat; 1300 m); and following exercise and at rest at 4270 m and 5150 m. Compared with the baseline BNP level at Kat (9.2+/−2 pg...

High altitude exposure leads to a marked natriuresis and diuresis facilitated by a reduced resting and subdued post-exercise aldosterone. There is a strong correlation between aldosterone and cortisol at high altitude and although most, but not all, investigators report a rise in cortisol with ascent very little data exist regarding the post-exercise response in cortisol. We therefore measured salivary cortisol in a cohort of 45 subjects post-exercise and 20 subjects at rest w...