European journal of applied physiology and occupational physiology
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Eur J Appl Physiol Occup Physiol · May 1999
The effect of dynamic exercise on resting cold thermoregulatory responses measured during water immersion.
The purpose of this study was to evaluate the effect of exercise on the subsequent post-exercise thresholds for vasoconstriction and shivering measured during water immersion. On 2 separate days, seven subjects (six males and one female) were immersed in water (37.5 degrees C) that was subsequently cooled at a constant rate of approximately 6.5 degrees C x h(-1) until the thresholds for vasoconstriction and shivering were clearly established. Water temperature was then increased to 37.5 degrees C. ⋯ Likewise, the shivering threshold increased from 36.2 (0.3) degrees C to 36.5 (0.3) degrees C post-exercise (P < 0.05). In contrast to the post-exercise increase in cold thermal response thresholds, sequential measurements demonstrated a time-dependent similarity in the Pre- and Post-Control thresholds for vasoconstriction and shivering. These data indicate that exercise has a prolonged effect on the post-exercise thresholds for both cold thermoregulatory responses.
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Eur J Appl Physiol Occup Physiol · May 1999
Skin-prick blood samples are reliable for estimating Hb mass with the CO-dilution technique.
Investigation of the impact of environmental stimuli such as altitude exposure on hemoglobin mass currently rely on invasive techniques that require venous blood sampling. This study assessed the feasibility of lancet skin pricks as an alternative to venepuncture to estimate hemoglobin mass with the carbon monoxide (CO) dilution technique, with the intent of making the technique accessible to technicians without phlebotomy training. Sixteen healthy volunteers rebreathed CO via a small-volume rebreathing apparatus. ⋯ Compared to VEN, Hb mass derived from CAP samples was overestimated by 1.7% (15+/-22 g Hb, p = 0.01). CAP samples to estimate Hb mass demonstrated a technical error of measurement of 2.7%, which is comparable to the 1.9% reported previously with VEN samples. We conclude that using CAP samples gives a reliable measure of %HbCO, and will make the estimation of Hb mass with the CO-technique accessible to technicians without phlebotomy training.