Growth hormone is released in a significant bolus during the first cycle of deep slow-wave sleep and will be missed if that specific window is delayed.

“growth hormone release happens all day long and all night long, but the deep, slow wave sleep that you get the very first sleep cycle is when you get a big bolus of growth hormone release, in men and women equally. And if you miss that first deep, slow wave sleep period, you also miss that big bolus”