Pulmonary ventilation and energy expenditure were measured on 6 subjects (car test drivers) during driving tests, with and without seat belts of the three-point type, on a ring circuit, both in a clockwise and a counterclockwise direction, and on up- and downhill winding road. The 6 subjects performed alternately as drivers and front passengers.

It resulted statistically certain that the use of seat belts reduced both the pulmonary ventilation and the energy expenditure of drivers in the counterclockwise test and of passengers in the clockwise test, i.e. when, on account of the dislodging force direction strong contractions of skeletal muscles were required of the subjects to maintain body balance. A similar saving in energy expenditure was recorded for both drivers and passengers during the uphill and downhill tests on winding roads.

Different factors, such as vehicle speed, seat belt type and individual functional characteristics, can have a bearing on results.