title: Timing of deep breaths during rest and light exercise in man.
abstract: 1. We used digital filtering techniques and segmental analysis to dissect a series of respiratory variables into three components: (a) outlying values, including deep breaths or sighs; (b) random variation; (c) non-stationary baseline variation. 2. Records of about 30 min breathing were obtained from normal adults at rest and at 50 W exercise. 3. Deep breaths were defined as having a tidal volume greater than 2.5 sd above the mean. 4. We related these deep breaths to preceding trends in tidal volume and end-tidal partial pressure of CO2. 5. At rest, there was no relation between deep breaths and tidal volume, but the deep breaths were significantly clustered around the troughs in end-tidal partial pressure of CO2. 6. At 50 W exercise, there was no relation between deep breaths and end-tidal partial pressure of CO2, but the deep breaths were significantly clustered around tidal volume troughs. 7. Results obtained by pneumography were concordant with those obtained by using a mouthpiece to measure ventilation.
authors.affiliation: Department of Medicine, St George's Hospital Medical School, London.
authors.forename: C P
authors.initials: CP
authors.lastname: Patil
authors.forename: K B
authors.initials: KB
authors.lastname: Saunders
authors.forename: B M
authors.initials: BM
authors.lastname: Sayers
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010313:Partial Pressure; D005082:Physical Exertion / Q000502:physiology*; D012119:Respiration; D012146:Rest / Q000502:physiology*; D013990:Tidal Volume; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide