Heat Stress and Physiological Strain of Permeable vs. Impermeable CB Protective Garment

Study Overview
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Brief Summary
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Current protective clothing of any kind, especially the nuclear-biological-chemical (NBC) protective garments, amplify thermal stress because of the inherent properties of the clothing material. High insulation coefficient and low water vapor permeability of the protective cloth limit the ability of sweat to readily evaporate, which consequently result with a significant elevation of body temperature and with excessive body fluid loss (because of inefficient sweating) that might result with significant dehydration. Combat soldiers require to perform intense physical activities under hostile environmental conditions, including in contaminated areas that need the use of protective garments. The ability to fulfill a mission derives from the soldier's professionalism and from his physiological limits. It is well established that wearing protective garments affect tolerance time (TT) and performance. To operate in contaminated areas suitable protective garments should be worn. The inherent characteristics of the current protective garments limit, however, the effective working periods with such an ensemble, which is further aggravated in hot climate. Thus, in an attempt to increase TT and enhance work effectiveness, improved protective garments, which result with a lessened heat-stress, are under different stages of development. The relative influence of air permeability properties, garment weight and garment construction on heat stress and physiological strain will be investigated. The results will be quantified in terms of body temperatures, heart rate, fluid balance, subjective sensation and the maximum wear time (if necessary extrapolated).

Conditions
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Heat Tolerance

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Twelve young (20-30 yr) male subjects will voluntarily participate in this study. The potential participants will be informed of the study's nature, purpose and medical risks. Their inclusion in the study requires the medical clearance by the study's physician (CRF) and after having filled out and sign an informed consent form Exclusion Criteria: heart conditions, blood pressure higher than 140/90 mmHg, known diabetes or any skin illness or lesions. Also be excluded are potential participants who were ill during the 2 weeks prior to the study

Ages Eligible for Study
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Minimum Age: 20 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| men wearing Semipermeable garment<br> | |
| air permeable garment type BP2<br> | |
| air permeable garment type BP3<br> | |
| air permeable garment type MO<br> | |
| air permeable garment type BP1<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The physiological burden of different CB Protective Garments | The physiological burden of different CB Protective Garments will be mesured by a heat tolerance test (HTT). The subjects will undergo an HTT wearing different CB Protective Garments and the results which indicate physiological burden will be compared between the different garments. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rectal temperature | The rectal temperature will be mesured by rectal thermistore. | 1 year | 
| Skin temperature | The skin temperature will be mesured by skin thermistores conected to 3 different sites (chest, leg and arm). | 1 year | 
| Heart rate | Heart rate will be mesured by a polar watch. | 1 year | 
| Sweat rate | The sweat rate will be calculated in each HTT from the subject's weight before and after the test and his water balance. | 1 year |