Repeated hyperthermia exposure increases circulating Brain Derived Neurotrophic Factor levels which is associated with improved quality of life, and reduced anxiety: A randomized controlled trial.

CONTEXT: Hyperthermia is known to be beneficial to patients affected by various diseases. Brain Derived Neurotrophic Factor (BDNF) is a marker of neuroplasticity usually increased as response to acute exposure to human body stressors. Little is known about BDNF changes after repeated exposure to hyperthermia. OBJECTIVE: To investigate the effect of a repeated hyperthermia exposure programme (HTC) on serum BDNF in healthy humans. DESIGN, SETTING, PARTICIPANTS: Randomized, single-blind, controlled trial in healthy humans conducted at Sechenov University Physiology Laboratory between December 2016 and November 2018. The treatment period was 10 weeks. Researchers analysing serum BDNF and questionnaires data were blinded to participants allocation. PARTICIPANTS: Were 34 healthy male (age 20.2 ± 1.6 years). INTERVENTION: Repeated Hyperthermia exposure programme, HTC, versus Light Intermittent Exercise, LIE, programme as control (10 weeks). MAIN OUTCOME MEASURE: Change in BDNF from baseline to final visit three days after treatment completion. RESULTS: 25 participants were analyzed. One participant withdrew before signing the informed consent and 8 participants (n = 3 in HTC and n = 5 in LIE) could not undertake the first assessment and were excluded. Mean change in BDNF was higher in HTC group vs LIE after both time points (after 12 and after 24 sessions). After 24 sessions BDNF was 30170 (SD 5268) pg/ml in HTC group a value that was significantly higher than 24104 (SD 2876) pg/ml measured in LIE group. BDNF concentrations were significantly higher than baseline values in HTC group only, 30170 (SD 5268) vs 26710 (SD 5437) pg/ml. CONCLUSION: A 10-week programme consisting of repeated exposure to hyperthermia resulted in a significantly higher increase of circulating BDNF compared to a programme consisting of intermittent light intensity exercise.

Redox Homeostasis in Humans Exposed to Intermittent Hypoxia-Normoxia and to Intermittent Hypoxia-Hyperoxia.

Aim: Exposure to hypoxia is known to increase oxidative stress and to impair antioxidant defenses in humans. The aim of the study was to measure oxidative stress and antioxidant capacity in healthy humans after being acutely exposed to both intermittent hypoxia-normoxia (IHN) and intermittent hypoxia-hyperoxia (IHH). Methods: Twenty-one healthy, young male participants were exposed to both IHN and IHH (fraction of inspired oxygen [FIO2] 0.11 for up to 7 minutes followed by 3-5 minutes of exposure to normoxia (room air) or hyperoxia, FIO2 0.3-0.35) in a crossover design study. In each participant, oxidative stress and antioxidant capacity were measured before and after each exposure in both experimental conditions. Results: After IHN, compared with baseline, neither oxidative stress (289.1 ± 63.2 vs. 262.2 ± 85.2 UCarr) nor antioxidant capacity (2376.1 ± 452.9 vs. 2525.0 ± 400.7 UCor) was significantly different. After IHH, neither oxidative stress (285.1 ± 94.2 vs. 277.5 ± 86.7 UCarr) nor antioxidant capacity (2653.6 ± 492.7 vs. 2568.4 ± 427.4 UCor) was significantly different compared with baseline. When the two studied exposure modalities were compared, there was no significant difference between groups with respect to both oxidative stress and antioxidant capacity. Conclusions: These data suggest that exposing healthy individuals to short-term IHN and IHH does not increase oxidative stress and it does not impair antioxidant defenses.