Whole-body repeated hyperthermia increases irisin and brain-derived neurotrophic factor: A randomized controlled trial.

CONTEXT: Hyperthermia is known to be beneficial to patients affected by various diseases. Irisin is a key regulators of fat metabolism known to be released as response to cold. Brain Derived Neurotrophic Factor (BDNF) is a marker of neuroplasticity usually increased as response to acute exposure to human body stressors. OBJECTIVE: Effect of a repeated hyperthermia exposure programme on changes in circulating irisin and serum BDNF in healthy humans. DESIGN: Setting, Participants: Randomized, single-blind, cross-over trial in healthy humans conducted at Sechenov University Physiology Laboratory from April 2019. The treatment period was 2 weeks (wash-out 3 weeks). Researchers analysing serum biomarkers and questionnaires data were blinded to participants allocation. Participants were 20 healthy male (age 21.5 ± 2.1 years). INTERVENTION: Hyperthermia exposure programme (WBPH) versus sham exposure (SHAM) to hyperthermia (10 sessions in two weeks). MAIN OUTCOME MEASURE: Changes in irisin and BDNF before and after short hyperthermia exposure. RESULTS: Twenty participants were analyzed. Irisin increased significantly in group WBPH only: 6.3 µg/ml (mean with SD = 1.6) compared to 5.4 µg/ml (SD = 1.7) in SHAM group; This value was also higher than baseline (5.0 mean with SD = 1.1) in WBPH. After 10 sessions mean change in BDNF was higher in WBPH group vs SHAM: BDNF was 28,263 (SD = 4213) pg/ml in WBPH group and 24,064 (SD = 5600) pg/ml in SHAM group. BDNF concentrations were significantly higher than baseline values in WBPH group only, 28,263 (SD 4213) vs 25,888 (SD 4316) pg/ml. CONCLUSION: In healthy young humans a 2-week, ten sessions programme consisting of repeated exposure to hyperthermia resulted in a significantly higher increase of circulating Irisin and BDNF.

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.