Does Staying Up Late Really Stunt Teenagers' Growth?

A senior paediatric endocrinologist has warned that staying up late can directly affect a teenager’s physical growth. Professor Dr Aman Bhakti Pulungan explained that growth hormones and other crucial hormones, particularly during puberty, are produced optimally when a child enters the deep sleep and rapid eye movement (REM) phases. “Sleep has a direct impact on growth. Growth hormones and certain other hormones, especially during puberty, are produced during deep sleep and the REM phase. Sleep is very influential,” Prof Aman said during a virtual discussion monitored in Jakarta on Wednesday (22/7/2026). He stressed that a child’s sleep duration must not be reduced. Teenagers aged 12 to 18 years require 8 to 9 hours of sleep and are strongly advised against staying up late. Prof Aman recommended that teenagers begin sleeping by 9 PM at the latest to allow the body’s natural circadian rhythm to work optimally, as this is when the body releases maximum growth hormones to support bone and muscle development. “Deep sleep cannot be discounted. I have had teenage patients say they sleep at midnight on weekends and wake up at 9 AM. That is not permissible, because growth hormones have a specific working time and period,” he stated. He noted that teenagers living in Indonesia have an advantage because the light and dark cycles are relatively regular throughout the year, a condition that should be utilised to ensure sufficient sleep. He cited examples of Japan, where the sun can rise around 4 AM, making the diurnal rhythm easier to disrupt, and Finland, where there are phases when the sun sets around 11 PM. Despite this, people in those countries try to create a dark atmosphere at home, for instance by closing curtains, so children can still sleep on time. “In Indonesia, we should be grateful because the dark sky is regular and long. This condition should be optimised so that Indonesian children have good physical growth and grow tall,” he said.