Effects of two cooling strategies on thermoregulatory responses of tetraplegic athletes during repeated intermittent exercise in the heat.

Athletes with spinal cord injury (SCI), and in particular tetraplegia, have an increased risk of heat strain and consequently heat illness relative to able-bodied individuals. Strategies that reduce the heat strain during exercise in a hot environment may reduce the risk of heat illness. To test the hypotheses that precooling or cooling during intermittent sprint exercise in a heated environment would attenuate the rise in core temperature in tetraplegic athletes, eight male subjects with SCI (lesions C(5)-C(7); 2 incomplete lesions) undertook four heat stress trials (32.0 +/- 0.1 degrees C, 50 +/- 0.1% relative humidity). After assessment of baseline thermoregulatory responses at rest for 80 min, subjects performed three intermittent sprint protocols for 28 min. All trials were undertaken on an arm crank ergometer and involved a no-cooling control (Con), 20 min of precooling (Pre), or cooling during exercise (Dur). Trials were administered in a randomized order. After the intermittent sprint protocols, mean core temperature was higher during Con (37.3 +/- 0.3 degrees C) compared with Pre and Dur (36.5 +/- 0.6 degrees C and 37.0 +/- 0.5 degrees C, respectively; P < 0.01). Moreover, perceived exertion was lower during Pre (13 +/- 2; P < 0.01) and Dur (12 +/- 1; P < 0.01) compared with Con (14 +/- 2). These results suggest that both precooling and cooling during intermittent sprint exercise in the heat reduces thermal strain in tetraplegic athletes. The cooling strategies also appear to show reduced perceived exertion at equivalent time points, which may translate into improved functional capacity.

The effect of a short-term mental stressor on neutrophil activation.

Twenty-five undergraduates and university staff (15 females, 10 males) volunteered to take part in a study examining the effects of a short-term mental stressor on the activation of neutrophils in peripheral blood, as determined by the oxidative capacity to reduced Nitro-blue Tetrazolium (NBT). Participants were assigned to one of two groups, an experimental group (n=17) and a control group (n=8). Subjects in the experimental group were subjected to a time-constrained mental stressor and finger-stick blood samples were taken on four occasions. Those in the control group did not complete a stressor task and only experienced the four finger-stick blood samples. Heart rate was recorded at 5-min intervals as a general indicator of arousal. Examination of the stained blood samples showed that a short-term stressor resulted in significant increased activation of neutrophils, which returned almost to baseline levels on completion of the experiment. In contrast, the control group's neutrophils showed no significant change in activation throughout. The results support the hypothesis that short-term, acute stressors may activate neutrophils.

The effect of odour priming on cortical EEG and visual ERP responses.

Two studies are reported that were designed to examine the way in which subjects, when primed with an olfactory stimulus, make perceptual judgements regarding subsequent congruent/incongruent information. The paradigm used was based on a modified version of a standard ERP semantic priming procedure. Subjects watched a computer screen and made a decision as to whether an image was congruent or incongruent with a priming olfactory stimulus. Results of the two studies showed significant effects in the N400 component of the visual ERP between congruent and incongruent stimuli are reported when a complex malodour accord was used as a prime but not when a complex pleasant odour accord was used as a prime.