title: Impact of physical fitness on salivary stress markers in sedentary to low-active young to middle-aged men.
abstract: Salivary cortisol (sCort) and alpha-amylase (sAA) are popular measurement tools for investigating hypothalamic-pituitary-adrenal and autonomic functioning, respectively. Despite their widespread use, only little is known about whether lifestyle factors such as regular exercise and physical fitness impact these two salivary stress markers. The lack of an objectively assessed fitness status is a major drawback of nearly all previous studies in this area. Our main objective was therefore to examine the impact of fitness status on sCort and sAA responses to a validated stressor.
  
  
  
  Sedentary to low-active men (N=115, 45.7±10.1 years, 26.7±3.4kg/m(2)) were exposed to the Trier Social Stress Test for Groups and provided saliva samples before and repeatedly after the stressor. An ergometer lactate exercise test provided information on physical fitness, that is, power achieved at the individual anaerobic threshold relative to body weight. From age-specific percentiles, a 2- (n=65 low fitness, n=50 high fitness) and a 3-group (n=37 low fitness, n=49 moderate fitness, n=29 high fitness) solution were calculated to elucidate the impact of different fitness levels.
  
  
  
  Prior to stress testing, sCort and sAA levels were similar in all groups. While both markers increased significantly due to stress exposure, fitness effects appeared rather small. When applying the 3-group solution, we observed attenuated sCort slopes in high- and moderate-fit men. Although sAA response slopes were pronounced in high-fit men, they failed to reach statistical significance. Mean stress reactivity (area under the curve with respect to ground, baseline, and response maximum) did not differ between groups and no association with fitness level was found.
  
  
  
  Our findings suggest only a weak effect of objectively assessed physical fitness on biological stress responses with attenuated hypothalamic-pituitary-adrenal but (non-significantly) higher autonomic responses in fitter men. Physical fitness is a factor that should not be neglected in future studies employing salivary stress markers, especially in studies interested in acute stress responses.
authors.affiliation: Clinical Biopsychology, Dept. of Psychology, University of Marburg, Germany. Electronic address: jana.strahler@gmail.com.
authors.forename: Jana
authors.initials: J
authors.lastname: Strahler
authors.affiliation: Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fuchs
authors.affiliation: Clinical Biopsychology, Dept. of Psychology, University of Marburg, Germany.
authors.forename: Urs M
authors.initials: UM
authors.lastname: Nater
authors.affiliation: Sport and Exercise Psychology, Dept. of Life Sciences, University of Roehampton, London, United Kingdom.
authors.forename: Sandra
authors.initials: S
authors.lastname: Klaperski
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010809:Physical Fitness / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000378:metabolism; D012463:Saliva / Q000378:metabolism*; D055291:Salivary alpha-Amylases / Q000378:metabolism; D057185:Sedentary Behavior; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D055291:Salivary alpha-Amylases; D006854:Hydrocortisone
keywords: Physical fitness; Salivary alpha-amylase; Salivary cortisol; TSST-G