The CPR Guidelines recommended that the rescuer is replaced every minute. However, it is difficult in the first moments to carry out the relays with such cadence and, therefore, it may be necessary to prolong the CPR time of each rescuer. Physical fatigue has a significant effect on the quality of external chest compressions (ECC), which can decrease after as few as 1–5 min of CPR. Percentage or maximal heart rate (%RMHR) and effort perception (EP) were parameters usually analysed to evaluate the effort of the rescuer during CPR. The aims of this study were to analyse college students while they performed CPR on a manikin for three minutes, the following: 1) the optimal cut-off points of arms muscle strength to perform adequate ECC, 2) physiological response (%RMHR), and 3) the PE.
Materials and Methods: Quasi-experimental study involving one hundred and twenty-five subjects. We determined the body mass index, arms muscle strength (handgrip) and EP. Participants performed three minutes of CPR on a manikin. The study protocol was approved according to the Helsinki declaration.
Results: The best cut-off point for predicting successful ECC using ROC curves were 21.75 kg for handgrip dynamometry. The maximal HR in CPR values were significantly higher in woman. These differences disappeared when controlling covariates. Also %EMHR was significantly higher in women, and this difference remained when controlling covariates. There are not significant differences by sex in maximal PE.
Conclusions: The effort required to perform three CPR minutes does not imply a great physical demand.