Introduction Despite of sustainable living and increasing the knowledge of the future mothers, the number of preterm births have been at the same level through last years. In Poland it is stands at around 7%, comparable with other countries from European Union. The aim was to investigate the influence of prematurity on input power and regulation power during stress test in adult women. Achieved power depends on the level of physical efficiency and it is converted for specific VO2max values. Material and methods 11 women born prematurely at age of 25-30 years (28,2± 2,3) did stress test according to W150 protocol. The control group consisted of 15 women born on time (27-32, 28,5±2,4). The statistical analysis included t-Student and Shapiro-Wilk tests. Index height/regulation power and BMI/ regulation power have been subjected to correlations. Results There is statistical significant difference between input and regulation power in women born prematurely and the control group. Women from control group had significantly higher input and regulation power than women born premature. Moreover, there is propor-tionality between input and regulation power in two groups. Conclusions 1. Prematurity influences the amount of power generated in women aged 25-30 negatively – women born prematurely are evidently less physically efficient than women born on time. 2. There is a connection between input and regulation power in both groups. Higher amounts of input power indicates higher amounts of regulation power. 3. There is no relationship between BMI and amounts of power in stress test.