Physiological effects of breathing resistance in equipment for measurements of aerobic energy expenditure

The project aims to study breathing resistance in flow meters, valves, mixing chambers and respiratory hoses, as well as its effects on athletes pulmonary ventilation and aerobic energy expenditure.

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The development of large treadmills has made it possible to study several sports more sport-specific than previous indoor experiments. Prior to the large treadmills, for example, the maximum oxygen absorption of cross-country skiers and skiers was examined during work on an ergometer bike or a small treadmill. Now, this is done by roller skiing on large treadmills that allow for both classic and freestyle techniques.

However, with the large treadmills, the distance between the subject on the treadmill and the stationary energy measurement systems alongside the treadmill has become wider compared to similar measurements made on the ergometer bike and the smaller treadmills. A wider distance between the system sensors and the subject on the treadmill therefore implies the need for longer hoses for the distribution of in- and exhalation air, which also results in increased breathing resistance.

Hardware such as valve housings, hoses, flow meters and mixing chamber for aerobic energy measurement systems are available in different fabrics, materials and geometries, which means different resistance to airflow, i.e. different resistance to breathing. At some point, resistance to breathing reaches a level that affects the subjects' ventilation and aerobic energy metabolism.

The aim of the project is therefore to study whether the breathing resistance in the energy measurement systems has a negative effect on the athletes’ ventilation and oxygen uptake. The result is expected to be of great interest to both manufacturers of energy measurement systems and its users.