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

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…

Serum concentrations of collagen degrading enzymes and their inhibitors after downhill running

In the present study the release of proteins degrading extracellular matrix compounds to circulation was measured after damaging exercise in humans. Muscle damage was induced by downhill running; furthermore, the exercise was performed at both cold temperature (5 degrees C) and room temperature (22 degrees C) to study also the possible effect of environmental temperature on serum concentrations of matrix metalloproteinases MMP-2 and MMP-9, tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2, and MMP-2/TIMP-2 complex, and muscle damage monitored by serum creatine kinase measurements. Results were compared with those obtained from patients having rhabdomyolysis, myositis and Becker musc…

Energy reserves of the capercaillie Tetrao urogallus in finlan

Abstract 1. 1. The size of energy reserves, distribution of fat stores and the fatty acid composition of subcutaneous and pericardial adipose tissue of capercaillie (Tetrao urogallus) were studied in 12 adult birds shot in Sept.–Oct. and in 8 birds shot in March. Furthermore 4 captive birds were killed in Sept. 2. 2. A capercaillie male can maintain or even increase its body weight during winter, but as shown in the present work it is not a result of increased fat content. 3. 3. In general, capercaillie seems to contain more stored energy in the form of fat than other tetraonids so far studied, except Svalbard ptarmigan. 4. 4. In males total fat content in percentage of body weight varied o…

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…