For transgender women (TW) undergoing estrogen therapy (ET), physiological responses while exerting physical effort is unknown at many points. Objective: To evaluate the behavior of respiratory gases along with ergospirometry in TW undergoing long-term GAHT Methods: A cross-sectional study was carried out with 15 TW (34.2±5.2 yo), 14 cisgender men (CM) and 13 cisgender women (CW). The TW received ET for 14.4 ±3.5 years. Ergospirometric test was performed. Results: Expiratory volume (VE) was similar among groups in the rest and AT points, and an approximation was observed between the pattern of TW and CW at the peak (P>0.05), both lower than CM (TW vs CM p<0.01; CW vs CM p<0.0001). The ventilatory equivalent for oxygen (VE/O2) and for carbon dioxide (VE/CO2) presented similar patterns among groups in all points (p>0.05). The end-tidal CO2 partial pressure (PetCO2) of TW was similar to that of CW during the test (p>0.05), and both were lower than that of CM at all points (p<0.05 at rest, AT and RCP; p >0.05 at peak. Discussion: The physiological curves of respiratory parameters of TW were mostly similar to the CW group. The VE pattern may be a consequence of ET. The VE/VO2 and VE/CO2 show that TW are adapted to this new condition. Conclusion: The behavior of TW gases during exertion showed a similar physiological pattern to CW.