Post-exercise cold water immersion does not alter high intensity interval training-induced exercise performance and Hsp72 responses, but enhances mitochondrial markers.

Abstract

This study aims to evaluate the effect of regular post-exercise cold water immersion (CWI) on intramuscular markers of cellular stress response and signaling molecules related to mitochondria biogenesis and exercise performance after 4weeks of high intensity interval training (HIIT). Seventeen healthy subjects were allocated into two groups: control (CON, n = 9) or CWI (n = 8). Each HIIT session consisted of 8-12 cycling exercise stimuli (90-110% of peak power) for 60s followed by 75s of active recovery three times per week, for 4weeks (12 HIIT sessions). After each HIIT session, the CWI had their lower limbs immersed in cold water (10°C) for 15min and the CON recovered at room temperature. Exercise performance was evaluated before and after HIIT by a 15-km cycling time trial. Vastus lateralis biopsies were obtained pre and 72h post training. Samples were analyzed for heat shock protein 72kDa (Hsp72), adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) assessed by western blot. In addition, the mRNA expression of heat shock factor-1 (HSF-1), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 and 2 (NRF1 and 2), mitochondrial transcription factor A (Tfam), calcium calmodulin-dependent protein kinase 2 (CaMK2) and enzymes citrate synthase (CS), carnitine palmitoyltransferase I (CPT1), and pyruvate dehydrogenase kinase (PDK4) were assessed by real-time PCR. Time to complete the 15-km cycling time trial was reduced with training (p < 0.001), but was not different between groups (p = 0.33). The Hsp72 (p = 0.01), p38 MAPK, and AMPK (p = 0.04) contents increased with training, but were not different between groups (p > 0.05). No differences were observed with training or condition for mRNA expression of PGC-1α (p = 0.31), CPT1 (p = 0.14), CS (p = 0.44), and NRF-2 (p = 0.82). However, HFS-1 (p = 0.007), PDK4 (p = 0.03), and Tfam (p = 0.03) mRNA were higher in CWI. NRF-1 decrease in both groups after training (p = 0.006). CaMK2 decreased with HIIT (p = 0.003) but it was not affected by CWI (p = 0.99). Cold water immersion does not alter HIIT-induced Hsp72, AMPK, p38 MAPK, and exercise performance but was able to increase some markers of cellular stress response and signaling molecules related to mitochondria biogenesis.