Physiological Limits of Exercise in Full-Body Protective Clothing*

János Pórszász, József Tasnádi, Badaoui Bechara, Miklós Ludván and Gábor Galgóczy

National Institute of Occupational Health, Budapest, Hungary
 
Corresponding author: János Pórszász, MD, Ph.D.
National Institute of Occupational Health
Budapest, P.O.Box 22.
Phone: (+36) 1 215 7890
FAX: (+36) 1 215 6891
e-mail: 100324.2440@CompuServe.com

* A part of this study has been presented at the 13th National Congress of the Hungarian Society for Occupational Health (with international participation), Budapest, 1995.

CEJOEM 1997, 3:242-257


Key words:
Exercise tolerance, full body protective clothing, tympanic temperature

Abbreviations:
ATS = American Thoracic Society;
dTtymp = increase in tympanic temperature above the baseline value (·C);
EWR = estimated work rate;
HR = heart rate (bpm);
IDLH = immediately dangerous to life and health;
ISS = initial steady state;
LAT = lactic acidosis threshold;
NTS = normal training suit;
SCBA = self contained breathing apparatus;
VCO2 = carbon dioxide output per minute (L/min, STPD);
VE = minute pulmonary ventilation (L/min, BTPS);
VO2 = oxygen consumption per minute (L/min, STPD).


Abstract:
The purpose of the present study was to test the effect of full-body protective clothing on exercise tolerance and the limiting physiological changes. Three types of protective clothing (ISOTEMP 4000, ISOTEMP 5500 and SUNIT-GUMOTEX V/a) with different weight and heat insulation characteristics were tested on seven healthy male subjects. The exercise tolerance was studied under thermoneutral conditions (room temperature and humidity) in ramp test, two constant work rates (80% LAT and 10% delta) (ISOTEMP-4000 and ISOTEMP-5500) and in a randomized work rate protocol on treadmill. Wearing the protective clothing effected in lower achievable external work rates while the physiological strain was the same. The duration of the constant work rates as well as the randomized test was limited by an appreciable extent depending on the actual work rate and type of test applied (18%–54%). The least limitation was found in case of the small-weight G-V/a type clothing. In addition to the limitation accountable for the excess weight the subject has to carry the heat strain caused by the impeded heat dissipation mechanisms contributes to the increase in physiological strain. It is emphasized that the level (i.e. in respect to the individual LAT), type (constant/impulsive) and duration of work needs to be closely regulated while working in full-body protective clothing under extreme work conditions. Since the core temperature continues to rise in recovery it is necessary to take the clothing off as soon as possible after the task has been accomplished and/or the allowable time limit has reached. This study has shown that the use of full-body protective clothing can lead to extreme strain, therefore, it is suggested that the persons selected for the use of full-body protective clothing and the SCBA should prove their excellent exercise tolerance. In addition, a regular exercise training program should help to maintain the excellence in fitness.
Received: 28 July 1997
Accepted: 25 August 1997

Posted: 25 November 1998

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