Lower heart rate variability (HRV) is known to make patients more susceptible to tachycardia and possibly sudden unexpected death in epilepsy (SUDEP). The heart rate (HR) at which tachycardia is present may vary by age. To date, no study has been done comparing adult and child seizures at different time points. The purpose of this study was to compare the frequency of HR changes with ictal tachycardia (IT) seizures at different time points in adults versus children. We retrospectively assessed the changes in the HR of 99 IT seizures in children and 96 IT seizures in adults. The difference between adults and children in gender, hemispheric lateralization or sleep/wakefulness, or seizure type on the HR changes and the difference between children and adults during 10 s preictal, ictal onset, and ictal and 60 s postictal were separately assessed. The HR difference and maximum HR increase with aging in children. The seizure duration in adults lasted longer as compared with that in children. There are higher HR at different points and HR difference at 10 s preictal as compared to baseline in children. The study illustrates that age and duration were respectively related to HR differences distinguishing children from adults. There may be an age-related effect of HR changes associated with seizures, with higher HR at different times and HR difference at 10 s before seizure onset as compared to baseline in children, which might explain that children are more likely to predict epileptic seizures than adults, contributing to subclinical seizures and treatment efficiency in refractory patients.