The Apple Watch would be trained to use its sensors to determine when a swimmer is showing signs of irregular behavior while in the water. The patent application notes, “In some embodiments, the swimming metrics and other information (e.g., heart rate, blood oxygen levels) are input into a machine learning model that has been trained to classify a swimmer showing regular or irregular behaviour when in the water.”


Illustration from Apple’s patent application
Sensors such as the heart rate monitor and the pulse oximeter, which measures blood oxygen levels, would be very useful in determining whether an Apple Watch user is drowning. Apple writes in the patent application, “When a swimmer is in distress (e.g., due to a heart attack), the user’s underwater behaviour becomes irregular. The irregular behaviour is reflected in the swimming analytics metrics and other information, such as heart rate or other vital signs.” The feature could also warn lifeguards, pool attendants, and parents when a child has crossed into the deep end of the pool, according to the patent application.
Apple points out that 3,500 people in the U.S. drown every year. The company also notes that while there are already systems available that combine live video feeds with object recognition software to determine if a swimmer is in trouble, those systems can produce false “drowning” readings and swimmers can also block the cameras.
Just because Apple filed this patent application last September, it does not mean that the company will be granted a patent. And even if it does, there is no guarantee that this technology will end up in a future iteration of the Apple Watch.