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The negative effects of heat stress on health, physiologic function and capacity to perform prolonged exercise or work are well described in literature. However, it remains difficult to quantify th...

Background People with spinal cord injury (SCI) have an altered afferent input to the thermoregulatory center, resulting in a reduced efferent response (vasomotor control and sweating capacity) below the level of the lesion. Consequently, core body temperature rises more rapidly during exercise in individuals with SCI compared with people who are able-bodied. Cooling strategies may reduce the thermophysiological strain in SCI. Objective The aim of this study was to examine the effects of a cooling vest on the core body temperature response of people with a thoracic SCI during submaximal exercise. Methods Ten men (mean age=44 years, SD=11) with a thoracic lesion (T4–T5 or below) participated in this randomized crossover study. Participants performed two 45-minute exercise bouts at 50% maximal workload (ambient temperature 25°C), with participants randomized to a group wearing a cooling vest or a group wearing no vest (separate days). Core body temperature and skin temperature were continuously measured, and thermal sensation was assessed every 3 minutes. Results Exercise resulted in an increased core body temperature, skin temperature, and thermal sensation, whereas cooling did not affect core body temperature. The cooling vest effectively decreased skin temperature, increased the core-to-trunk skin temperature gradient, and tended to lower thermal sensation compared with the control condition. Limitations The lack of differences in core body temperature among conditions may be a result of the relative moderate ambient temperature in which the exercise was performed. Conclusions Despite effectively lowering skin temperature and increasing the core-to-trunk skin temperature gradient, there was no impact of the cooling vest on the exercise-induced increase in core body temperature in men with low thoracic SCI.

Item does not contain fulltext BACKGROUND: Exercise increases core body temperature (Tc), which is necessary to optimise physiological processes. However, excessive increase in Tc may impair performance and places participants at risk for the development of heat-related illnesses. Cooling is an effective strategy to attenuate the increase in Tc. This meta-analysis compares the effects of cooling before (precooling) and during exercise (percooling) on performance and physiological outcomes. METHODS: A computerised literature search, citation tracking and hand search were performed up to May 2013. 28 studies met the inclusion criteria, which were trials that examined the effects of cooling strategies on exercise performance in men, while exercise was performed in the heat (>30 degrees C). 20 studies used precooling, while 8 studies used percooling. RESULTS: The overall effect of precooling and percooling interventions on exercise performance was +6.7+/-0.9% (effect size (ES)=0.43). We found a comparable effect (p=0.82) of precooling (+5.7+/-1.0% (ES=0.44)) and percooling (+9.9+/-1.9% (ES=0.40)) to improve exercise performance. A lower finishing Tc was found in precooling (38.9 degrees C) compared with control condition (39.1 degrees C, p=0.03), while Tc was comparable between conditions in percooling studies. No correlation between Tc and performance was found. We found significant differences between cooling strategies, with a combination of multiple techniques being most effective for precooling (p

Item does not contain fulltext The presence of impaired thermoregulatory and fluid balance responses to exercise in older individuals is well established. To improve our understanding on thermoregulation and fluid balance during exercise in older individuals, we compared thermoregulatory and fluid balance responses between sexagenarians and octogenarians during prolonged exercise. Forty sexagenarians (60 +/- 1 year) and 36 octogenarians (81 +/- 2 year) volunteered to participate in a 30-km march at a self-selected pace. Intestinal temperature (T in) and heart rate were recorded every 5 km. Subjects reported fluid intake, while urine output was measured and sweat rate was calculated. Octogenarians demonstrated a lower baseline T in and a larger exercise-induced increase in T in compared to sexagenarians (1.2 +/- 0.5 degrees C versus 0.7 +/- 0.4 degrees C, p < 0.01), while maximum T in tended to be higher in octogenarians (38.4 +/- 0.4 degrees C versus 38.2 +/- 0.3 degrees C, p = 0.09). Exercise intensity (70 +/- 11 % versus 70 +/- 9 %) and exercise duration (7 h 45 min +/- 0 h 57 min versus 7 h 24 min +/- 0 h 58 min) were not different between octogenarians and sexagenarians. Octogenarians demonstrated lower fluid intake (251 +/- 97 mL/h versus 325 +/- 125 mL/h, p = 0.01) and urine output (28 +/- 22 mL/h versus 52 +/- 40 mL/h, p < 0.01) compared to sexagenarians. Furthermore, the sweat rate tended to be lower (294 +/- 150 mL/h versus 364 +/- 148 mL/h, p = 0.07) in the octogenarian group. Sodium levels and plasma volume changes were not different between sexagenarians and octogenarians (all p > 0.05). These results suggest that thermoregulatory responses deteriorate with advancing age, while fluid balance is regulated appropriately during a 30-km walking march under moderate ambient conditions. 01 december 2014

Item does not contain fulltext Exercise results in an increase in core body temperature (Tc), which may reduce exercise performance and eventually can lead to the development of heat-related disorders. Therefore, accurate measurement of Tc during exercise is of great importance, especially in athletes who have to perform in challenging ambient conditions. In the current literature a number of methods have been described to measure the Tc (esophageal, external tympanic membrane, mouth or rectum). However, these methods are suboptimal to measure Tc during exercise since they are invasive, have a slow response or are influenced by environmental conditions. Studies described the use of an ingestible telemetric temperature pill as a reliable and valid method to assess gastrointestinal temperature (Tgi), which is a representative measurement of Tc. Therefore, the goal of this study was to provide a detailed description of the measurement of Tgi using an ingestible telemetric temperature pill. This study addresses important methodological factors that must be taken into account for an accurate measurement. It is recommended to read the instructions carefully in order to ensure that the ingestible telemetric temperature pill is a reliable method to assess Tgi at rest and during exercise.