The Effect of Smoking on Thermoregulation

Study Overview
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Brief Summary
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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 Description
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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.

Official Title
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The Effect of Smoking on Thermoregulation

Conditions
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Cigarette Smoking

Intervention / Treatment
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* Drug: Nicotine
* Other: cigarette smoking


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 18-30 healthy after medical checkup after signing concent form for the smokers: smoking 0.5-1.5 packs of cigarettes a day at least 2 years. Exclusion Criteria: heart disease respiratory disease baseline bp above 140/90 mmHg diabetes anhydrosis skin disease acute illness detoxification from nicotine allergy to nicotine smoking other then specified in the inclusion criteria

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: smokers<br>This arm consists of smokers. | Drug: Nicotine<br>* both groups will be given nicotine lozenges before a VO2 test and a HTT.<br>Other: cigarette smoking<br>* the smokers will smoke 2 cigarettes before a VO2 exam and a HTT.<br>|
| Active Comparator: non-smokers<br>non-smoking participants in the study | Drug: Nicotine<br>* both groups will be given nicotine lozenges before a VO2 test and a HTT.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heat tolerance | 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. | 2-3 days | 
| VO2max | 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. | 2-3 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rectal temperature | 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 | experimental days 4,5,6 | 
| Heart rate | During the HTT and the VO2 test heart rates will be monitored continuously and will be stored by a heart rate wristwatch, (POLAR, Finland). | experimental days 4,5,6 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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smoking, exercise, heat tolerance, heat stroke