The Impact of Pre-Cooling as an Intervention Strategy to Minimize Cardiovascular system Essay Example for Free

The Impact of Pre-Cooling as an Intervention St come outgy to Minimize Cardiovascular system EssayThe bugger off of this report was to in enthroneigate whether the physical exercise of pre-cooling (cooling vest) prior to a 10, 000m road-race run inside a hot and humid environment, would result in improved performance. The report similarly aimed to examine any performance-related effects, and their underlying physiologic mechanisms.Fourteen (n=14) well-trained adult runners participated in two 10,000m- beat trials, spaced 72 hours apart. Ambient chinks of both the mark and experimental conditions were T= 32.5 C, rel. humidity= 65% and T= 32.8C, rel. humidity= 63% respectively. Procedure consisted of a 30 minute warm up (20 minutes steady state trial at RPE 13, 10 minutes individualized stretching activity). During the warm up, the chasten condition required participants to wear a normal tee shirt, with the experimental condition requiring participants to wear a commerci wh ollyy available gel-based cooling vest. Conclusion of the 30 min warm up saw the tee shirt or ice- vest replaced with the race singlet, before commencing the 10, 000 m time trial. Time, pre and post body mass, heart rate, scrape temperature and incumbrance temperature were all variables measured and record.Participants were able to complete the 10,000m road-run in less(prenominal) time following the pre-cooling condition, suggesting that pre-cooling as an intervention strategy improved endurance performance. Results indicate this spendrence was due to materially lower kaleing core and beat temperatures, reduced starting heart rate as well as an everywhereall lower sweat rate. These factors allowed for a great capacity of ignite stock, minimizing thermoregulatory and cardiovascular strain and therefore allowing the body to operate at a higher level of performance before reaching critical limiting temperature.Results Figure 1 displays the difference betwixt time trials obta ined in both the find out and pre-cooling conditions. The pre-cool time trial was significantly shorter than the control time trial (p0.05).The difference between service line and post body mass (BM) were record to calculate sweat rate (L/hr.). Figure 2 displays the difference in sweat rate between the control and pre-cool conditions. Control sweat rate was significantly higher then sweat rate recorded for the pre-cool condition.The above graph (Figure 3) depicts the mean heart rates and standardised deviations for both control and pre-cool conditions. HR was recorded and displayed over three phases of the time trial (start, mid and end). Statistical analysis determined that there was a significant difference in HR between the three phases of the time trial (p0.05). Statistical significance also occurred between control start HR and pre-cool start HR, with control start HR 5.10% greater than pre-cool start HR.Skin temperature was also recorded and statistically analysed. Figure 4 displays the mean and standard deviations for skin temperature (Tsk) over three phases of the time trial for both the control and pre-cool conditions. Significant differences between both control and pre-cool conditions were found (p0.05). Significant statistical differences were also discovered between each of the phases of the time trial (p0.0167).Figure 5 depicts mean and standard deviations for core temperature (Tc). Significant statistical difference occurred between the three different stages of the time trial (p0.05). When compared separately, significant differences were found between all stages of the time trial (start vs. mid, start vs. end, mid vs. end) (p0.0167).DiscussionThe purpose of this study was to investigate whether pre-cooling through the utilization of a cooling vest would augment endurance performance undertaken in the heat. Findings obtained from the study indicate that pre-cooling did improve performance, as the pre-cooling condition time trials were signifi cantly shorter than the control condition (p0.05). This ability to perform at a higher intensity, decreasing time taken to complete the 10,000m run can be explained by the physiological mechanisms behind pre-cooling.The ability to exercise under hot and humid conditions is significantly impaired (Nielsen, Hales, Strange, Christensen, Warberg Saltin, 1993) when ambient temperature exceeds skin temperature. Reduced heat loss that would normally occur through convection and radiation, results in an increase in body temperature (Marino Booth, 1998). By lowering pre-performance body temperature, the bodys ability to capacitate metabolic heat drudgery is increased (Siegel Laursen, 2012), therefore increasing the time to reach critical limiting temperature, at which exercise performance deteriorates or can no longer be maintained (Marino et al. 1998).Sweat rate was lower following pre-cooling compared to the control condition. A number of studies have also obtained similar results, fin ding greater heat storage capacities and subsequent sweat rates as a result of precooling (Olschewski Bruck, 1988)(Lee Haymes, 1995)(White, Davis Wilson, 2003). This can be explained by the greater heat storage, that is stimulated by precooling, delaying the onset of heat dissipation and subsequent sweat threshold (White et al. 2003). Furthermore, by minimizing sweat rate, the flow of blood to the skin surface is also reduced. This allows more blood to be distributed to the fighting(a) muscles, reducing cardiovascular strain (White et al, 2003).Another physiological mechanism stimulated through pre-cooling, that aids in reducing cardiovascular strain is heart rate (HR)(Kay, Taaffe Marino, 1999). Recorded data over both conditions showed an increase in HR from the start to the end of the time trial. However, the only significant difference between control and precooling was found between the starting HR recordings. The precooling start HR was 5.10% lower than the control start H R (p0.0167).This significant difference was not maintained passim mid and end recordings, with both the control and precooling end HR reaching approximately 191 bpm. Kay et al. (1999) found similar results, with HR slightly reduced following precooling within the first 20 minutes of exercise, however this difference was not maintained at 25 and 30 minutes of exercise. A review of relevant publications by Marino (2002) also indicated a lower HR during the start of exercise that was not seen passim the rest of the exercise bout. These findings can be explained by greater primeval blood volume, a result of reduced body temperature and therefore no need to distribute blood flow to skin to lose heat. A greater central blood volume produces an increase in stroke volume, ultimately reducing HR and cardiovascular strain (Marino, 2002).Skin temperature results were also recorded over three phases of the time trial. Similar to HR, a significant difference between control and precooling st art skin temperature recordings were found (p0.0167), but diminished throughout the remaining two phases of the time trial. Through the use of precooling and consequent lower skin temperature recordings, blood flow was not required at the skin, centrally deny blood volume and assisting in reducing cardiac strain (Drust, Cable Reilly, 2000).The final variable assessed in this study was core temperature. According to Neilsen et al. (1993), high core temperature is the most important factor leading to exhaustion and impaired performance during exercise under hot and humid conditions. This may be due to intelligence and core body temperature having a corresponding relationship. Therefore, an increase in core temperature may result in an increase in brain temperature, resulting in central fatigue and affecting motor performance (Nybo, 2012). Core temperature results showed similarities to the findings for HR and skin temperature. Statistical significant differences were found between each phase that core temperature was recorded (p0.05)(start, mid and end time trial), showing a gradual rise from the start of the time trial to the end. A comparison of means via a T-test between start core temperature (control) and start core temperature (precool) showed a significant difference (p0.0167), which was not seen between samples during mid and end time trial.The findings from this study indicate and award the benefits precooling has on improving endurance performance in hot and humid environments. A number of studies and reviews studying precooling as an intervention strategy (Kay et al. 1993)(Marino, 2002)(Marino et al. 1998) have all shown the positive physiological mechanisms that arise from precooling. Time trials were significantly shorter in time following precooling, showing an improvement in performance. The significantly lower heart rate, skin temperature and core temperature stimulated by precooling at the start of the time trial, all contribute to a greater capacity for metabolic production. This greater capacity provides cool subjects with the ability to work at a higher intensity for longer, before critical limiting temperature is reached, ultimately improving endurance performance.