Introduction People with type 1 diabetes are recommended to exercise regularly. However, limited evidence exists on how frequency and duration of exercise affect the risk of hypoglycemia. The study aimed to compare the percentage of time spent in hypoglycemia between two 5-day periods with different frequency and duration of physical activity. Research design and methods In this outpatient randomized crossover study, 26 participants aged 18-65 years with type 1 diabetes for ≥2 years and insulin pump use for ≥1 year were included. After a 7-day observation period, participants completed two 5-day intervention periods separated by a washout period of at least 14 days. One period included five exercise sessions on 5 consecutive days (5S), each consisting of 4 min of resistance training and 30 min of aerobic exercise. Another period included two exercise sessions on 2 days with at least 2 days in between (2S), each consisting of 10 min of resistance training and 75 min of aerobic exercise. During each period, participants performed in total 150 min of aerobic exercise and 20 min of resistance training and wore continuous glucose monitors (Dexcom G6) and accelerometers (ActiGraph wGT3X-BT). Results Twenty insulin pump-treated adults (10 women) with type 1 diabetes completed the study. The baseline median (range) age was 48 (24-64) years, glycated hemoglobin 55 (44-66) mmol/mol, diabetes duration 24 (8-57) years, and body mass index 28.4 (22.3-35.8) kg/m 2. No differences were observed between 5S and 2S in the percentage (mean±SD) of time spent below 3.9 mmol/L (3.5%±2.8% vs 4.5%±4.2%, p=0.28), time spent in 3.9-10.0 mmol/L (65.3%±15.0% vs 68.5%±13.6%, p=0.31), time spent above 10.0 mmol/L (31.2%±16.4% vs 27.3%±14.5%, p=0.15), mean glucose (8.7±1.3 mmol/L vs 8.5±1.2 mmol/L, p=0.33) and glycemic variability (35.8%±5.3% vs 35.8%±6.6%, p=0.97). Conclusions Time spent in hypoglycemia was comparable between the two 5-day periods with different duration and frequency of physical activity. Trial registration number NCT04089462.