(Image credit: Future) When you're trying to sleep well, there common rules, like no caffeine after 2pm, no phones in the bedroom. But sleeping in 90 minute segments probably isn't a habit many people strive to implement. Yet as a sleep writer-cross-early bird, it's one I rely on night after night. In fact, I'd say my secret to waking up with energy lies in the '90 minute sleep rule.' Key takeaways: At a glance Based off the length of a typical sleep cycle, the 90 minute sleep rule ensures you complete all essential sleep stages. The aim is to wake up in the light sleep stage when your body and brain are more primed to rise. Science shows that sleeping at consistent times and waking up gradually can boost your health, longevity, and performance. Sleep and wake timings are just as important as overall sleep duration, and tracking your sleep can help you establish and stick to a consistent routine. What is the 90 minute sleep rule?…