In the Sleep Status diagram, the horizontal and vertical axes show the current time and sleep state such as deep sleep, light sleep, or awake. You can read the sleep status at specific periods from the diagram.
Y-axis shows the sleep status categorized in colors and measured in height. The X-axis shows two important time periods: the time you started Sleep Tracking and the time you stopped Sleep Tracking.
You can also read sleep latency on the diagram. Sleep latency is the period of time between the time you started Sleep Tracking and when you fell into your first light sleep. It's marked in yellow and displays how long it takes for you to fall asleep after starting Sleep Tracking.