Heat acclimation improves mental vigilance of Paralympic shooting athletes:British Association of Sport and Exercise Science Annual Conference, Essex

Athletes with spinal cord injury are at a greater risk of heat illness during exercise in the heat and suffer a reduction in exercise capacity (Webborn et al. 2005; J Appl Physiol, 98, 2101-2107). Heat acclimation can improve thermoregulation and mental skills tasks of able body athletes (Walker et al. 2001; Comp Biochem Physiol, Part A, 128, 701-707), but less is known about athletes with spinal cord related disease. Therefore, the aim of this study was to investigate the effect of seven days heat acclimation (HA) upon thermoregulation and vigilance of Paralympic shooting athletes. Five Paralympic shooters (age 40.2, s = 18 yr) with spinal cord related disease (two T9/10 complete lesion; one C5/6 complete lesion; one, T4 polio with no motor or sensory function; and one T6 spina bifida with no motor function) consented to take part in the study that was approved by the institutional ethics committee. Participants completed seven days HA in an environmental chamber set at 33.4, s = 0.6oC, 64.8, s = 3.7 % relative humidity. Each HA session lasted 60 min and consisted of 20 min arm crank exercise at 50, s = 5 W followed by passive rest or optional simulated shooting. Aural canal temperature (Taur) and perceived thermal comfort were measured throughout. Vigilance scores were assessed using a high speed, visual number display, consisting of three numbers that flashed on screen 100 times in a 2 minute period with an 8% duplication rate (Hope et al. 1998; Anasth, 53, 545-550). When two of the three numbers were identical the participant hit the space bar to score a ‘HIT’. If participants missed the identical numbers a ‘MISS’ was scored, and when they incorrectly indicated the numbers a ‘FALSE’ was scored. Resting core temperature reduced from 36.3, s = 0.2oC on day 1, to 36.0, s = 0.2oC on day 7 (P = 0.02). Mean Taur during the HA session on day 1 was 37.2, s = 0.2 oC and this reduced to 36.7 s = 0.3oC on day 7 (P = 0.01). Ratings of thermal comfort on day 1 were 5.1, s = 0.2 units, and this reduced to 4.5, s = 0.4 units on day 7 (P = 0.00). Vigilance scores can be seen in Table 1.Table 1. (Mean, s,) vigilance scores (HIT, MISS FALSE) pre and post heat acclimation (HA) and the P values of differences between pre and post HA. Vigilance Score (mean, s) HIT MISS FALSEPre HA 9.2, s = 1.8 5.8, s = 1.8 4.2, s = 1.7Post HA 12.4, s = 2.0 2.4, s = 2.0 1.8, s = 1.5P Value 0.012 0.01 0.03To our knowledge this is the first study to show that HA improves mental vigilance of elite athletes with spinal cord related disease. An enhanced heat storage adaptation (Price and Campbell 2002; J Sports Sci 20(7):519-27) may have reduced the set point for core temperature (Buono et al. 1998 J App Physiol, 274(43), R1295-R1299). The subsequent improvement in thermal comfort may explain the enhanced vigilance scores when heat acclimated. Heat acclimation can improve thermoregulation and mental vigilance of Paralympic shooting athletes, which may assist performance in hot conditions