title: Cold pressor response in high landers versus low landers.
abstract: BACKGROUND
  Native high landers face two main environmental challenges i.e. hypobaric hypoxia and low ambient temperatures. Both factors contribute to increased sympathetic stimulation and increased blood pressure. Despite these challenges, subjects living at high altitude have lower systolic and diastolic pressures as compared to subjects living in plains. Present study investigated cold pressor test (CPT) which is a potential predictor of future hypertension in high landers and low landers Materials and Methods: Vascular reactivity in terms of changes in systolic and diastolic blood pressure and heart rate in response to cold pressor test has been compared in high lander (n=45) and low lander (n=46) population.
  
  
  RESULTS
  Systolic and diastolic blood pressure changes and heart rate changes with cold pressor test are lower in high landers as compared to low landers. Females in both the groups in general exhibited greater cold pressor response than males.
  
  
  CONCLUSIONS
  Hypo-reactive cold pressor test is due to higher parasympathetic tone and lower sympathetic tone. Decreased cold pressor response in high landers reflects another adaptive modulation of sympatho-vagal activity that enables them to stay in hypobaric atmosphere and lower temperatures without undue autonomic stress.
authors.affiliation: Assistant Professor, Department of Physiology, King George's Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Jagdish
authors.initials: J
authors.lastname: Narayan
authors.affiliation: Associate Professor, Department of Physiology, King George's Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Archana
authors.initials: A
authors.lastname: Ghildiyal
authors.affiliation: Assistant Professor, Department of Physiology, All India Institute of Medical Sciences , Bhubaneswar, Odisha, India .
authors.forename: Manish
authors.initials: M
authors.lastname: Goyal
authors.affiliation: Associate Professor, Department of Physiology, King George's Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Dileep
authors.initials: D
authors.lastname: Verma
authors.affiliation: Professor, Department of Physiology, King George's Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Shraddha
authors.initials: S
authors.lastname: Singh
authors.affiliation: Professor, Department of Physiology, King George's Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Sunita
authors.initials: S
authors.lastname: Tiwari
keywords: Altitude; Autonomic; CPT; Hypertension; Parasympathetic; Sympathetic