title: Changes in pulse pressure, heart rate and the pulse pressure x heart rate product during squatting in Type 1 diabetes according to age.
abstract: OBJECTIVE
  We assessed changes in pulse pressure and heart rate during a squatting test, as indirect markers of arterial stiffness and cardiovascular autonomic neuropathy, respectively, according to age and sex in patients with Type 1 diabetes mellitus.
  
  
  METHODS
  We evaluated 160 diabetic patients, divided into four groups of 20 men and 20 women according to age (G1, 20-30 years old; G2, 31-40 years old; G3, 41-50 years old; and G4, 51-60 years old), and 160 non-diabetic matched control subjects. Each subject underwent a 3 min posture test (standing-squatting-standing) with continuous measurement of arterial blood pressure and heart rate by a Finapres device. Overall values throughout the test, baseline levels in initial standing position and squatting-induced changes in pulse pressure, heart rate and the pulse pressure x heart rate product were compared between diabetic patients and healthy control subjects.
  
  
  RESULTS
  In the standing position, a greater increase in pulse pressure and lower reduction in heart rate with age led to a significantly higher pulse pressure x heart rate product in diabetic patients compared with control subjects. In the squatting position, a more marked pulse pressure increase in the absence of appropriate reduction in heart rate resulted in a greater rise in the pulse pressure x heart rate product in diabetic patients than in healthy subjects. No major differences were noted between the sexes, with the exception of a stronger relationship between pulse pressure and age in the female population with diabetes. Squatting-derived indices of cardiovascular autonomic neuropathy were also noted with increasing age in diabetic patients.
  
  
  CONCLUSIONS
  The marked increase in the pulse pressure x heart rate product ('pulsatile stress') according to age, combined with cardiovascular autonomic neuropathy, may contribute to the higher cardiovascular risk of patients with Type 1 diabetes.
authors.affiliation: Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, CHU Sart Tilman, University of Liège, Liège, Belgium.
authors.forename: J-C
authors.initials: JC
authors.lastname: Philips
authors.forename: M
authors.initials: M
authors.lastname: Marchand
authors.forename: A J
authors.initials: AJ
authors.lastname: Scheen
mesh_terms: D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D012016:Reference Values; D014655:Vascular Resistance / Q000502:physiology*; D055815:Young Adult