Human Gene Response to Exercise in a Cold Environment

Purpose: To determine mitochondrial related gene expression response to exercise in a cold compared to room temperature environment. Methods: Recreationally trained males (n=9, age: 25±4 y, height: 179±5 cm, weight: 76.2±8.0 kg, %BF: 13.4±3.3%, VO2peak: 4.39±0.82 L/min) completed two trials consisting of cycling in a cold (C) or thermo-neutral (N) environment (7.2±0.2, 20.1±0.2 ⁰C, respectively) for one hour at 60% of Wmax followed by room 3 hours of room temperature recovery. Muscle biopsies were taken from the vastus lateralis pre-exercise and three hours post-exercise for gene expression analysis. Heart rate (HR) and expired gasses were also measured throughout the trials. Results: Exercise V02 was lower in C than N (2.68±0.8, 2.81±5.2 L/min, respectively, p=0.017). HR was similar during exercise and recovery between C and N (Exercise: 150±9 and 150±9 bpm, respectively, p=0.920; Recovery: 75±14 and 74±10 bpm, respectively, p=0.522). Environmental temperature (p=0.238) and V02 (p=0.924) were not different during recovery. PGC-1α and VEGF increased with exercise (p=0.001, p=0.001, respectively) but not between trials (p=0.134 and p=0.975, respectively). ERRα was lower in C than N (p=0.033). There was a trend in MEF2A and NRF2 being lower in C than N (p=0.086, p=0.055) but not with exercise (p=0.786, p=0.256). NRF1 and TFAM did not change between trials (p=0.981, p=0.854, respectively). Conclusion: These results indicate that when exercise is performed in a cold environment, select mRNA associated with mitochondrial biogenesis are altered