Dr. Hans Van Dongen, director of the Sleep and Performance Research Center, dives into how sleep loss and circadian misalignment affect brain function. He discusses his mathematical modeling of fatigue's impact on performance, revealing startling insights about cognitive deficits from chronic sleep deprivation. The conversation also highlights the biological basis of chronotypes and the serious implications for health, emphasizing the importance of proactive sleep management in high-stakes situations. Along the way, he shares personal anecdotes that shaped his path into sleep research.