Pre‐exercise whole‐body cooling decreases blood volume and oxygenated hemoglobin content in skeletal muscle during submaximal exercise (1106.7)

Irisin – ‘New Kid on the Block in energy regulation’?

Using Heart Rate Variability Methods for Health-Related Outcomes in Outdoor Contexts : A Scoping Review of Empirical Studies

Heart rate variability (HRV) is a psychophysiological variable that is often used in applied analysis techniques to indicate health status because it provides a window into the intrinsic regulation of the autonomic nervous system. However, HRV data analysis methods are varied and complex, which has led to different approaches to data collection, analysis, and interpretation of results. Our scoping review aimed to explore the diverse use of HRV methods in studies designed to assess health outcomes in outdoor free-living contexts. Four database indexes were searched, which resulted in the identification of 17,505 candidate studies. There were 34 studies and eight systematic reviews that met t…

Recovery of hormonal, blood lipid, and hematological profiles from a North Pole expedition.

INTRODUCTION This study examined the recovery patterns of hormonal, blood lipid, and hematological profiles following strenuous physical loading, continuous extreme cold exposure and energy deficit induced by a North Pole expedition. METHODS Seven men completed an 850-km North Pole expedition in temperatures varying from -3 degrees C to -47 degrees C. Daily energy intake was approximately 23 MJ x d(-1) and was composed of approximately 60% fat. Blood samples were collected 2 wk before (Pre) the expedition and after 2 wk (Post 1), and 2 mo (Post 2). Additional samples were collected on the first (R1), third (R3), and fifth (R5) return days. RESULTS Mean weight loss upon return was 10 kg. Ene…

The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lat…

Fuel selection during short-term submaximal treadmill exercise in the cold is not affected by pre-exercise low-intensity shivering.

Exercise and shivering rely on different metabolic pathways and consequently, fuel selection. The present study examined the effects of a pre-exercise low-intensity shivering protocol on fuel selection during submaximal exercise in a cold environment. Nine male subjects exercised 4 times for 60 min at 50% (LOW) or 70% (MOD) of their peak oxygen consumption on a motorized treadmill in a climatic chamber set at 0 °C with (SHIV) and without (CON) a pre-exercise cooling protocol, inducing low-intensity shivering. Thermal, cardiorespiratory and metabolic responses were measured every 15 min whereas blood samples were collected every 30 min to assess serum nonesterified fatty acids (NEFA), glyce…

The Effects of Cold Exposure on Leukocytes, Hormones and Cytokines during Acute Exercise in Humans

The purpose of the study was to examine the effects of exercise on total leukocyte count and subsets, as well as hormone and cytokine responses in a thermoneutral and cold environment, with and without an individualized pre-cooling protocol inducing low-intensity shivering. Nine healthy young men participated in six experimental trials wearing shorts and t-shirts. Participants exercised for 60 min on a treadmill at low (LOW: 50% of peak VO2) and moderate (MOD: 70% VO2peak) exercise intensities in a climatic chamber set at 22°C (NT), and in 0°C (COLD) with and without a pre-exercise low-intensity shivering protocol (SHIV). Core and skin temperature, heart rate and oxygen consumption were col…

The effects of exercising in the cold on energy metabolism, skeletal muscle tissue oxygenation and immuno-endocrine responses