I had an ecg attached to me and my qtc was 415ms then i started running and when my hr hit 134 did an ecg and qtc 457ms, is this because i didnt give my qt enough time to adapt?

QT intervals are notoriously difficult to measure accurately during exercise because of baseline artefacts. If the ECG was of good quality and the ECG waveforms are of good quality, an increase in the QT during exercise and an increased heart rate is abnormal and needs further evaluation including a family history, use of medications and the presence of electrolyte abnormalities.