Abstract:

Incremental exercise test contains three different metabolic regions, including aerobic region, partly anaerobic and anaerobic dominated region. The work load from warm up period to anaerobic threshold (AT) was accepted as aerobic region, workload above AT to respiratory compensation point (RCP) was accepted partly anaerobic region and above RCP was accepted as anaerobic region of incremental exercise test. We aimed to compare the ventilatory patterns during different metabolic sections of incremental exercise test. Fifteen healthy males performed an incremental exercise test (15 W/min) to exhaustion on a cycle ergometer. Metabolic and cardiopulmonary parameters were measured breath-by-breath using metabolic gas analyser system and turbine volume meter. AT and RCP were estimated using ventilator and pulmonary gas exchange parameters. Respiratory patterns, breathing frequency (Bf) and tidal volume (VT), showed great differences among the exercise regions. VT is the main factor increases minute ventilation (VE) during aerobic region. However, Bf becomes dominant factor increasing VE in anaerobic region of test. In the region between AT to RCP, Bf and VT showed similar effects on increase in VE. VT to inspiratory time ratio increased significantly in all region of test. However, work production capacity for each liter of VE decreased markedly when the exercise intensity changed from aerobic to anaerobic regions. Consequently, evaluation of breathing patterns for different metabolic regions of incremental exercise will provide information regarding individual's metabolic strength and ventilator response. 

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