title: Aerobic exercise and cold pressor test induce hypoalgesia in active and inactive men and women.
abstract: BACKGROUND
  Physical inactivity is a risk factor for chronic pain. Several mechanisms play a role in pain chronification including impairment of pain inhibition.
  
  
  OBJECTIVE
  This study compared the efficiency of pain inhibitory systems between physical active and inactive healthy subjects. It was hypothesized that active subjects had more efficient pain inhibition compared with inactive subjects.
  
  
  METHODS
  A randomized, crossover study with 2 days of data collection.
  
  
  METHODS
  Fifty-six (28 females) subjects participated in this study. Subjects were subgrouped into active (n = 30) and inactive (n = 26). Conditioned pain modulation (CPM) was assessed by cold pressor testing. Exercise-induced hypoalgesia (EIH) was assessed after 15 minutes bicycling at a heart rate corresponding to 75% VO2max. A control session of 15 minutes quiet rest was also included. Pressure pain thresholds (PPTs) were recorded at the dominant arm and leg before, immediately after, and 15 minutes after conditioning and exercise as well as before and after rest. PPTs were also recorded during conditioning.
  
  
  RESULTS
  At baseline, PPTs in inactive men were increased compared with inactive women (P < 0.003). During cold pressor test and after exercise, PPTs increased to the same degree in active and inactive subjects, and the CPM and EIH responses were correlated (P < 0.05). The CPM response immediately after cold pressor test was maintained in women but not in men.
  
  
  CONCLUSIONS
  Cold pressor stimulation and aerobic exercise caused comparable multisegmental increases in PPT in active and inactive men and women. The CPM and EIH responses were correlated, but they have different temporal manifestation of hypoalgesia.
authors.affiliation: Pain Center South, University Hospital Odense, Odense, Denmark.|Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Henrik Bjarke
authors.initials: HB
authors.lastname: Vaegter
authors.affiliation: Pain Center South, University Hospital Odense, Odense, Denmark.
authors.forename: Gitte
authors.initials: G
authors.lastname: Handberg
authors.affiliation: The Institute of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
authors.forename: Maria N
authors.initials: MN
authors.lastname: Jørgensen
authors.affiliation: The Institute of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
authors.forename: Anna
authors.initials: A
authors.lastname: Kinly
authors.affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Graven-Nielsen
mesh_terms: D000328:Adult; D003080:Cold Temperature; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology*; D055815:Young Adult
keywords: Conditioned Pain Modulation; Exercise-Induced Hypoalgesia; Pain Modulation; Physical Activity; Pressure Pain Thresholds