The effect of infrared radiation emitting garments on the acute skeletal muscle molecular signalling responses to high-intensity interval exercise.

Infrared radiation (IR) has previously been demonstrated to activate signalling pathways involved in mitochondrial biogenesis and angiogenesis. We tested the hypothesis that IR emitting fabric (IREF) would enhance translocation and phosphorylation of proteins, and mRNA expression of genes, associated with mitochondrial biogenesis and angiogenesis in response to high-intensity interval exercise (HIIE) compared to non-IREF. Eleven males (age, 22 ± 4 yrs, V̇O2peak, 48.0 ± 4.6 ml·kg-1·min-1) completed two HIIE sessions consisting of 10 x 3 min intervals at a power output equivalent to 60% of the difference between gas exchange threshold and peak power output. Each interval was interspersed by 3 min at 25 W. In a repeated-measures, counter balanced, single-blind design, participants wore IREF and non-IREF clothing (SHAM) before, during and following HIIE. Muscle biopsies were obtained pre (Baseline), immediately post (PE) and 3 hours post exercise (3hPE). Cytosolic and Nuclear p-CaMKII content were both greater PE in IREF compared to SHAM (P = 0.001 and P = 0.003 respectively). Cytosolic and Nuclear p-p38 MAPK content increased from baseline to PE in IREF (P = 0.008 and P = 0.005, respectively) but not SHAM. NRF1 and TP53 mRNA expression were greater in IREF compared to SHAM PE (P ≤ 0.013) and 3hPE in NRF1 only (P = 0.002). There was no change in the phosphorylated protein content or gene expression of any angiogenesis related target in IREF compared to SHAM. Wearing IREF before, during and following HIIE augments some of the acute cellular signalling cascades associated with mitochondrial biogenesis.