There is no option to turn on the Pulse Ox feature during an activity specifically. You have the option to have it on all day, during sleep, or for spot checking. When All-Day Mode is enabled, the watch will sample your SpO2 levels every 5-15 minutes. If the watch detects a high level of movement (e.g. out for a run) it will read less often. When viewing Pulse Ox widget on the watch, you will see the average of readings for each hour. You could perhaps set it on All-Day Mode before you start an activity, but I am not sure if it will get a reading since you are supposed to be motionless. Let me know if you have any further questions!
