Maximal stress test performance while wearing a self-contained breathing apparatus

J Occup Med. 1977 Dec;19(12):802-6. doi: 10.1097/00043764-197712000-00005.


Fifteen adult male volunteers (mean age = 31.0 years; eight non-smokers and seven smokers) carried out a Bruce protocol maximal treadmill stress test under four separate conditions. These four conditions were (1) without Scott Air Pak (SAP) respirator; (2) with SAP respirator apparatus but not wearing face mask; (3) with SAP apparatus, wearing face mask in "demand" breathing mode; and (4) with SAP respirator apparatus, wearing face mask in "pressure-demand" breathing mode. The data indicate that the overriding factor in the approximately 20% decrement in work performance during conditions 2, 3, and 4 was related to the weight of the SAP respirator (15.8 kg), P less than 0.05. Only during condition 3 did eight of 15 subjects report lack of air as one reason for termination. Conditions 3 and 4 resulted in a significant decrease in TFore (2.5 degrees C) and was primarily related to the decreased Tinsp which reached a maximum decrement of 9.7 degrees C. Under all conditions the smokers' work time was significantly less than nonsmokers, P less than 0.05.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Blood Pressure
  • Coronary Disease / etiology*
  • Coronary Disease / prevention & control
  • Exercise Test*
  • Fires
  • Heart Rate
  • Humans
  • Male
  • Occupational Diseases / etiology*
  • Occupational Diseases / prevention & control
  • Physical Exertion
  • Smoking
  • Stress, Physiological / physiopathology
  • Ventilators, Mechanical / adverse effects*