Why toddlers heartbeat rate faster while sleeping?

Toddlers have a higher resting heart rate compared to adults, typically ranging from 80 to 130 beats per minute. During sleep, their heart rate may fluctuate due to the different stages of sleep, particularly during REM sleep when brain activity increases. This faster heartbeat supports growth and development, as well as helps regulate their body temperature and metabolic processes. Additionally, their smaller heart size means that their heart pumps more frequently to meet their physiological needs.