Journal of Applied Physiology, Vol 47, Issue 6 1336-1339, Copyright © 1979 by American Physiological Society
A head-out exercise body plethysmograph
V. Niinimaa, P. Cole, S. Mintz and R. J. Shephard
A head-out exercise body plethysmograph has been developed to facilitate
investigations of the extrathoracic airways. An airtight seal around the
neck is provided by a pliable sheet of dental dam braced by a tubular bean
bag. A set of bicycle pedals is connected by a chain drive, axle, and
wall-mounted sealed ball bearing to an external ergometer. The box is
air-conditioned to allow exercise up to work loads of 200 W with a
temperature increase of less than 1 degree C above ambient laboratory
readings. Nose, mouth, and extrathoracic airways are easily accessible for
airflow and pressure measurements. O2, CO2, and humidity levels of respired
air are not disturbed, verbal communication with the subject is possible,
and the subject is unlikely to feel claustrophobic. The plethysmograph has
a flat frequency response to 4.2 Hz; it thus functions accurately in both
resting and exercise measurements of respiratory minute ventilation. The
plethysmograph can also be used for determinations of nasal and oral
airflow and pressure, and the study of breathing patterns.
