International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Performance and Health in Cold Climate

Introduction: There is a problem of conditioning of inspired cold air especially during physical loadings, accompanying with hyperventilation in circumpolar areas. Development of criteria of efficacy of airway heat exchange is possible at experimental modeling of extreme conditions by an inspiration of cold air in a regimen of a hyperventilation.

Study design: Measurement of temperature of exhaled air during cold air hyperventilation with the purpose of development of criteria of an estimation of airway conditioning.

Methods: Temperature of exhaled air was measured at 26 healthy people during 3-minute isocapnic hyperventilation with cold (-20°C) air at a level of 60% from maximal ventilation (on the average 81,4±7,0 l/min). The control of temperature was carried out by low inertion thermoresistor located in airflow at a mouth.

Results: When average temperature of inhaled air was -18,5±0,3°C, temperature of exhaled air was decreased from 32,7±0,2°C to 28,2±0,6°C (р<0,001) at the end of provocation. The fall of temperature of exhaled air (Т°ex) during hyperventilation is good approximated by a hyperbolic curve of a kind: Т°ex (°С) = 38,6/Т (s) + 28,2, where Т - duration of hyperventilation.

Comparison of temperature fall during ventilating loading with volume ventilated allows to calculate an index of air conditioning, which shows what volume of air is necessary during cold hyperventilation for fall of expired air temperature on 1°C and reflects conditioning reserves of the respiratory system. It was equal on the average 66,8±6,3 l/°С in healthy persons.

Conclusion: The reduction of conditioning reserves of the respiratory system can be diagnosed, if: а) temperature of expired air at any moment of isocapnic cold hyperventilation is lower than its level calculated on the upper equation; b) index of air conditioning is below of established normal level. The developed criteria allow to estimate airway heat exchange ability, to estimate reserves of air-conditioning that can be beneficial in clinical practice, and also for professional selection in extreme ecological conditions.

Note. Abstracts are published in author's edition

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Last update: 06-Jul-2012 (11:52:05)