It is very well known that women in reproductive period are naturally better protected against cardiovascular diseases than men of the same age. The reasons for these are not clear.

For better determination of possible differences between gender we measured ECG, systolic (SBP), diastolic (DBP) and pulse pressure (PP), heart rate (HR), variability of HR (HRV) and pressure, cardiac output (CO), stroke volume (SV) and peripheral vascular resistance (SVR) at rest, during mental stress (3 minutes of standard arithmetic challenge) and during recovery in the group of 24 healthy males and 38 aged-matched females (19–22 years old).

HR did not differ between both groups at rest and recovery after stress, but was statistically significant higher (p<0,05) during mental stress in females. There was no difference in SBP, DBP or PP at rest, during stress and during recovery. There were no differences in HRV, variability of SBP or DBP and in SV also. But CO was greater in females, especially during mental stress (p<0.05), and SVR was smaller in females at rest, during mental stress and during recovery (p<0.05) when compared to the group of males.

There were no differences in SBP or DBP between males and females. The main differences observed were in CO and SVR. The question arises: is increased systolic or diastolic pressure the main reason for cardiovascular diseases or the reason lies somewhere in the different CO or SVR between males and females?