Is it better to wake up between sleep cycles?

Waking from lighter sleep may feel easier than waking from deep sleep, which is why sleep-cycle calculators aim to place the alarm near an estimated cycle ending. However, a calculator cannot know your actual sleep stage, and cycles do not follow an exact 90-minute schedule. Total sleep duration and consistency have a much greater effect on daytime functioning than trying to time one perfect moment. You may feel refreshed after waking naturally near the end of a cycle, but cutting sleep short to reach a calculated boundary is unlikely to help. Smart alarms and wearables may estimate lighter sleep using movement and heart rate, but they are not as accurate as clinical sleep monitoring. Prioritize enough uninterrupted sleep first.