Clinical Trial: The Effect of Smoking on Thermoregulation

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: The Effect of Smoking on Thermoregulation

Brief Summary: To the best of our knowledge, a possible relation between smoking and heat injuries or heat intolerance was never scientifically examined, although such a relation is logical according to the observations that smoking has a thermogenic effect, decreases physical fitness and affects the body's heat dissipation.16 healthy young male volunteers will participate in the study, 8 smokers and 8 non-smokers. They will arrive to our lab four or six times. They will perform VO2 test and heat tolerance test (HTT) in different conditions.

Detailed Summary: 16 healthy young male volunteers will participate in the study, 8 smokers and 8 non-smokers. They will arrive to our lab four or five times. During their first visit they will go through a VO2 max test in order to evaluate their aerobic fitness, and their physiological efficiency. During their second visit all subjects will go through the same test after exposure to nicotine. During the smokers' third visit they will go through the same test, after exposure to cigarette smoking. During the non-smokers third visit and the smokers fourth visit - they will go through an exercise heat tolerance test without prior smoking. During the fifth visit the smokers will go through an exercise heat tolerance test after exposure to cigarette smoking. During the smokers' sixth visit and the non-smokers fourth visit they will go through an HTT after exposure to nicotine.
Sponsor: Sheba Medical Center

Current Primary Outcome:

• Heat tolerance [ Time Frame: 2-3 days ]
  The test is performed in a climatic chamber at a temperature of 40oC and 40% relative humidity. During the test, the subject walks on a treadmill at a speed of 5 km/hr at a 2% grade for 2h. Body core temperature and heart rate are continuously monitored, and sweat rate is computed from body weight prior to and after the test, corrected for fluid intake. Heat intolerance is determined when body core temperature elevates above 38.5oC, when heart rate elevates above 150 bpm, or when either does not tend to reach a plateau.
• VO2max [ Time Frame: 2-3 days ]
  volunteer's oxygen consumption (VO2) will be monitored continuously with a metabolic chart (ZAN), while running for 10 min on a treadmill under comfortable environmental conditions.

Original Primary Outcome:

• Heat tolerance [ Time Frame: change from baseline after smoking or nicotine ingestion ]
  The test is performed in a climatic chamber at a temperature of 40oC and 40% relative humidity. During the test, the subject walks on a treadmill at a speed of 5 km/hr at a 2% grade for 2h. Body core temperature and heart rate are continuously monitored, and sweat rate is computed from body weight prior to and after the test, corrected for fluid intake. Heat intolerance is determined when body core temperature elevates above 38.5oC, when heart rate elevates above 150 bpm, or when either does not tend to reach a plateau.
• VO2max [ Time Frame: change from baseline after smoking or nicotine ingestion ]
  volunteer's oxygen consumption (VO2) will be monitored continuously with a metabolic chart (ZAN), while running for 10 min on a treadmill under comfortable environmental conditions.

Current Secondary Outcome:

• Rectal temperature [ Time Frame: experimental days 4,5,6 ]
  The volunteers will undergo heat tolerance test. Their rectal temperature will be measured by rectal thermistor and will be monitored continuously and viewed by the attending medical staff. Automatically all data will be recorded by the monitoring Biopac system
• Heart rate [ Time Frame: experimental days 4,5,6 ]
  During the HTT and the VO2 test heart rates will be monitored continuously and will be stored by a heart rate wristwatch, (POLAR, Finland).

Original Secondary Outcome:

• Rectal temperature [ Time Frame: experimental days 4,5,6 ]
  The volunteers will undergo heat tolerance test. Their rectal tempreture will be mesured by rectal thermistor and will be monitored continuously and viewed by the attending medical staff. Automatically all data will be recorded by the monitoring Biopac system
• Heart rate [ Time Frame: experimental days 4,5,6 ]
  During the HTT and the VO2 test heart rates will be monitored continuously and will be stored by a heart rate wristwatch, (POLAR, Finland).

Dates:
Date Received: May 6, 2012
Date Started: June 2012
Date Completion:
Last Updated: May 8, 2014
Last Verified: May 2014