title: Heart rate variability and stress hormones in novice and experienced parachutists anticipating a jump.
abstract: BACKGROUND
  Chronic work stress and overtraining are known to influence heart rate (HR) and heart rate variability (HRV) at rest and decreased nocturnal HRV is associated with cardiovascular health and disease. The purpose of this study was to examine whether anticipation of an acute highly stressful event influences HR and HRV during the night and morning.
  
  
  METHODS
  Nocturnal HR and HRV and urinary stress hormones (cortisol, adrenaline, noradrenaline) as well as HR and HRV responses to an orthostatic test on the morning of a parachute jump day or control day were analyzed from 14 novice and 7 experienced parachute jumpers.
  
  
  RESULTS
  There were no differences in any HRV indices during the night or the orthostatic test between the jump and control situations. The novices had higher HR than experienced jumpers in the orthostatic test in the morning and also during the jump, but no differences were found between the groups in nocturnal HR and HRV indices or HRV indices during the orthostatic test. There were no differences in nocturnal stress hormone secretions except slightly elevated adrenaline secretion during the jump night compared to the control night (P = 0.014).
  
  
  CONCLUSIONS
  The parachute jump did not substantially influence HR, HRV, or stress hormones during the night or the orthostatic test in the morning preceding the jump. The results suggest that the parachute jump as an acute highly stressful event had no anticipatory effect on autonomic modulation of the heart even though both the novices and experienced jumpers had markedly accentuated sympathetic activation during the parachuting.
authors.affiliation: KIHU Research Institute for Olympic Sports, Jyväskylli, Finland. esa.hynynen@kihu.fi
authors.forename: Esa
authors.initials: E
authors.lastname: Hynynen
authors.forename: Niilo
authors.initials: N
authors.lastname: Konttinen
authors.forename: Heikki
authors.initials: H
authors.lastname: Rusko
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D001341:Autonomic Nervous System / Q000502:physiology; D001359:Aviation; D002940:Circadian Rhythm / Q000502:physiology*; D004837:Epinephrine / Q000652:urine; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000652:urine; D008297:Male; D018670:Monitoring, Ambulatory; D009638:Norepinephrine / Q000652:urine; D017286:Polysomnography; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology / Q000652:urine; D055815:Young Adult
chemical_list: D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine