Purpose. Physical activity is an integral part of the treatment of diabetes. The aim of the study was to assess aerobic capacity and cardiovascular-respiratory reactions to a single physical exercise with gradually increasing intensity in normobaric hypoxia in patients with Type 1 diabetes. Methods. The study was conducted on a sample of adults with Type 1 diabetes (GT1D, n = 13) and a randomly chosen healthy control (GK, n = 15). The study participants performed a progressive exercise test to exhaustion in normoxia (FiO₂ ~ 20.90%) and 7 days later in normobaric hypoxia (FiO₂ ~ 15.14%). At rest, during exercise, and after completion of the test blood was drawn and physiological indicators were monitored. Results. Two-way ANOVA revealed a significant effect of hypoxia and physical exercise on blood glucose concentrations (F = 6.1 p < 0.01). In GT1D , lower glucose levels were observed in normobaric hypoxia compared with baseline and post-exercise levels in normoxia (p < 0.05). A tendency to increased maximal oxygen uptake and significantly higher minute pulmonary ventilation was observed in both groups in response to exercise and hypoxia. Conclusions. Physical activity and hypoxia may effectively control glucose homeostasis and increase cardiorespiratory adaptation to exercise in Type 1 diabetics.