title: [Evaluation of stress levels during parachuting training by salivary biomarker].
abstract: OBJECTIVE
  To evaluate the stress level during parachuting training by salivary biomarker and to study the dynamic characteristics.
  
  
  METHODS
  Twenty recruits of military parachuting training completed 8 trainings in a month. The saliva samples were collected at 2 h and 1h before boarding and at 0.5 h after landing on the 1st, 4th and 7th trainings. The levels of cortisol, chromogranin A and α-amylase in saliva samples were detected.
  
  
  RESULTS
  The concentrations of cortisol, chromogranin A and activity of α-amylase increased significantly from pre-boarding to landing during 3 trainings. The concentrations of cortisol, chromogranin A and activity of α-amylase at 2 h before boarding and at 0.5 h after landing decreased significantly with the training times. However, the changes of 3 biomarkers at 1 h before boarding among 3 trainings were not significant.
  
  
  CONCLUSIONS
  The levels of stress increased significantly for 20 recruits from pre-boarding to landing during parachuting trainings. The stress levels of 20 recruits before boarding and after landing significantly decreased with parachuting training times.
authors.affiliation: Institute of Aviation Medicine, Air Force, Beijing, China.
authors.forename: Liang-en
authors.initials: LE
authors.lastname: Chen
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Zhang
authors.forename: Rui-qing
authors.initials: RQ
authors.lastname: An
authors.forename: Hao
authors.initials: H
authors.lastname: Zhan
mesh_terms: D001359:Aviation; D015415:Biomarkers / Q000032:analysis; D053379:Chromogranin A / Q000032:analysis; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D008297:Male; D012463:Saliva / Q000737:chemistry*; D013315:Stress, Psychological; D055815:Young Adult; D000516:alpha-Amylases / Q000032:analysis
chemical_list: D015415:Biomarkers; D053379:Chromogranin A; D000516:alpha-Amylases; D006854:Hydrocortisone