Roxanne Prichard, psychology and neuroscience professor at the University of St. Thomas College of Arts and Sciences, was quoted in a Live Science article on how the human circadian rhythm and various lifestyle factors can play into the "second wind" of energy.
From the article:
Part of the answer comes down to circadian rhythms, roughly 24-hour cycles largely controlled by part of the brain called the hypothalamus. For instance, a circadian rhythm helps regulate when we feel alert or drowsy. As part of this sleep-wake cycle, there's a period after sunset — known as the "wake maintenance zone" or "evening second wind" — when energy levels surge.
This happens because the body's wakefulness signals remain relatively high, while sleep-promoting signals, such as the sleep-promoting hormone melatonin, haven't fully kicked in yet, Roxanne Prichard, a professor of psychology with a background in neuroscience at the University of St. Thomas in St. Paul, Minnesota, told Live Science in an email.
From an evolutionary perspective, this burst of energy may have helped our ancestors complete essential tasks, "like making an evening meal and making sure there's a safe place to sleep," Prichard explained.
Typically, the wake maintenance zone lasts for a few hours, but its exact length varies from person to person, Prichard said. For night owls, this wake maintenance zone can be longer than those of "morning larks," who may experience a shorter second wind and find it comparatively easier to fall asleep early.
