Karen Birkenhead^1,, Chris Barnett², Colin Solomon¹

Physical exercise requiring oxidative energy transfer increases pulmonary ventilation (V_E). In an air polluted environment, the exercise-induced increase in V_E increases the volume of toxic gases and number of toxic particles to which the pulmonary system is exposed. Using a respiratory air-filtering device (RAFD) during exercise decreases exposure to inhaled toxic gases and particles. However, a RAFD creates external resistance to inspiration and expiration which could decrease pulmonary muscle function and pulmonary volumes, and creates an external mechanical dead-space which produces fractional rebreathing which could increase pulmonary flowrates. This experiment tested the hypotheses that using a RAFD during exercise would; decrease post-exercise peak inspiratory pressure (P_PI) and peak expiratory (P_PE) pressure, FVC and FEV₁, and increase post-exercise flowrates. Using a repeated-measures, counter-balanced design, six healthy moderately aerobically-trained, men (mean ± SD; age 24.7 ± 1.7 years; peak oxygen utilization [VO_2peak] 42.8 ± 5.3 ml kg^-1 min^-1) completed two 30 min exercise test sessions at a power output equal to 75% VO_2peak. One session was performed not using (NORAFD), and one using a RAFD (Moldex 8000) fitted with organic vapor cartridges and combined dust and mist pre-filters (inspiratory resistance = 0.216 kPa, expiratory resistance = 0.094 kPa at 85.0 l min^-1). All pulmonary function tests were performed immediately pre-(Pre) and 0 (Post-0), 5 (Post-5), and 15 (Post-15) min post-exercise. There was a significant (p<0.05) main effect of time with an increase in FEV₁, FEV₁/FVC%, PEF, and FEF_50% from Pre to Post-0. There were no other within or between condition differences in any of the pulmonary muscle pressures, volumes or flowrates. It was concluded that using a RAFD during moderate intensity medium duration exercise does not affect post exercise pulmonary function.

respiratory protection, pulmonary function, physical activity, exercise