Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure

Abstract

Extracellular heat shock protein 72 (eHsp72) concentration increases during exercise-heat stress when conditions elicit physiological strain. Differences in severity of environmental and exercise stimuli have elicited varied response to stress. The present study aimed to quantify the extent of increased eHsp72 with increased exogenous heat stress, and determine related endogenous markers of strain in an exercise-heat model. Ten males cycled for 90 min at 50 % V : O 2peak in three conditions (TEMP, 20°C/63 % RH; HOT, 30.2°C/51%RH; VHOT, 40.0°C/37%RH). Plasma was analysed for eHsp72 pre, immediately post and 24-h post each trial utilising a commercially available ELISA. Increased eHsp72 concentration was observed post VHOT trial (+172.4 %) (p <0.05), but not TEMP (−1.9 %) or HOT (+25.7 %) conditions. eHsp72 returned to baseline values within 24 h in all conditions. Changes were observed in rectal temperature (T rec ), rate of T rec increase, area under the curve for T rec of 38.5 and 39.0°C, duration T rec ≥38.5 and ≥39.0°C, and change in muscle temperature, between VHOT, and TEMP and HOT, but not between TEMP and HOT. Each condition also elicited significantly increasing physiological strain, described by sweat rate, heart rate, physiological strain index, rating of perceived exertion and thermal sensation.Stepwise multiple regression reported rate of T rec increase and change in T rec to be predictors of increased eHsp72 concentration. Data suggests eHsp72 concentration increases once systemic temperature and sympathetic activity exceeds a minimum endogenous criteria elicited during VHOT conditions and is likely to be modulated by large, rapid changes in core temperature.

Increasing heat storage by wearing extra clothing during upper body exercise up-regulates heat shock protein 70 but does not modify the cytokine response

“…Biochemical methods to detect protein concentrations with a sensitivity of down to 1 ng•mL −1 would therefore not be able to detect the true resting concentration or indeed any small increase from resting. This may partly explain why Gibson et al (2014) only detected HSP70 changes when T core changes were in excess of 2 ºC. However, it is important to note that the extent of the HSP change in the current study (16%) is a very modest increase when compared to existing studies investigating lower body exercise, where increases of 200-1600% have been documented (Yamada et al, 2008).…”

“…Given the importance of temperature elevations in this response (Welc et al, 2012), this exercise modality may particularly benefit from interventions increasing heat stress, because in contrast to lower body exercise, upper body exercise generates less metabolic heat and as such the increases in T core for the same relative exercise intensity are lower for this modality (Gass & Gass, 1998). Lower body exercise comparable in relative intensity and duration as the present study induces two to three times the increase in T core when performed in cool or thermo-neutral conditions (Gibson et al, 2014;Niess et al, 2003;. Previous studies support the hypothesis that exercise that results in a higher T core magnifies the IL-6 response when compared to a CON condition.…”

“…The importance of temperature on the HSP response is further reflected by the positive relationships that have previously been found between exercise duration and plasma HSP70 concentration and exercise intensity and plasma HSP70 concentration (Fehrenbach, Niess, Voelker, Northoff, & Mooren, 2005). Whilst some interventions have failed to document an increase in plasma HSP70 concentrations following exercise combined with moderate heat stress (Gibson et al, 2014), a number of studies summarised by Yamada et al (2008) have shown HSP70 elevations following moderate to exhaustive exercise. It is important to note that the sensitivity of the procedures to quantify HSP70 may affect any conclusions.…”

Salivary extracellular heat shock protein 70 (eHSP70) levels increase after 59 min of intense exercise and correlate with resting salivary secretory immunoglobulin A (SIgA) levels at rest

“…iHSP70 levels increase in response to exercise-induced stressors such as heat, reactive oxygen species (ROS), and hypoxia in cells (Fehrenbach and Northoff 2001). Actually, a single bout of exercise increases circulating eHSP70 level (Walsh et al 2001;Febbraio et al 2002;Fehrenbach et al 2005) and heat stress further boosts this increase (Gibson et al 2014). However, Fortes and Whitham (2011) reported that eHSP70 in the saliva unchanged during and until 20 min after the exercise (60 min of treadmill running at 50−70 % VO 2max ) with hot environment (30°C).…”

Effective microorganism – X attenuates circulating superoxide dismutase following an acute bout of intermittent running in hot, humid conditions

“…Increased extracellular heat shock protein 72 (eHsp72) concentrations are evident in response 61 to exercise with the greater increases 62 during exercise-heat stress predicted by the magnitude of change in rectal temperature 63 (Gibson et al, 2014) and exercise intensity (Periard, Ruell, Caillaud, & Thompson, 2012). 64…”