title: Cardiovascular responses to facial cooling are age and fitness dependent.
abstract: OBJECTIVE
  Aging of the cardiovascular system may be altered by differences in physical fitness. We investigated the cardiovascular responses to brief periods of facial cooling (5 degrees C) in 20 healthy men differing in age and aerobic fitness (VO2max).
  
  
  METHODS
  Facial cooling was administered at rest in the supine position during 60-s quiet breathing to 6 fit young (FY; VO2max = 75.8 +/- 18 mL x kg(-1) x min(-1); 29 +/- 7 yr), 6 sedentary young (SY; VO2max = 36.0 +/- 2.2 mL x kg(-1) x min(-1); 27 +/- 3 yr), 6 fit old (FO; VO2max = 56.1 +/- 4.0 mL x kg(-1) x min(-1); 54 +/- 5 yr), and 6 sedentary old (SO; VO2max = 29.6 +/- 5.0 mL x kg(-1) x min(-1); 62 +/- 2 yr) volunteers. The following were measured before and after facial cooling: heart rate (HR), mean arterial blood pressure (MAP), pressure-rate product (PRP), and M-mode echocardiographically determined left ventricular internal dimensions, peak circumferential shortening (peak V(CF)), and ejection fraction (EF).
  
  
  RESULTS
  Facial cooling produced a statistically significant bradycardia in all groups except for the SO whereas MAP was increased in the young groups but unchanged in the older groups. Pressure-rate product was significantly reduced in the FY, unchanged in the SY and FO, and significantly increased in the SO group. None of the groups showed a change in left ventricular dimensions, whereas only the SO group showed an increase in peak V(CF) (P < 0.05).
  
  
  CONCLUSIONS
  These data suggest that endurance training and fitness level do not significantly alter cardiovascular responses to facial cooling in young men or physically fit older men. However, in older subjects, a sedentary lifestyle appears to be associated with an absent facial cooling reflex bradycardia, an increased PRP, and contractility (peak V(CF)).
authors.affiliation: Faculty of Medicine, Department of Family Medicine and Physiology) University of Western Ontario, London, Canada. petrella@julian.uwo.ca
authors.forename: R J
authors.initials: RJ
authors.lastname: Petrella
authors.forename: D A
authors.initials: DA
authors.lastname: Cunningham
authors.forename: P M
authors.initials: PM
authors.lastname: Nichol
authors.forename: R
authors.initials: R
authors.lastname: Thayer
mesh_terms: D000328:Adult; D000367:Age Factors; D001341:Autonomic Nervous System / Q000502:physiology*; D003080:Cold Temperature; D005145:Face; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness; D012018:Reflex / Q000502:physiology