Straited I believe is the answer.
You could drown by such a small amount of water during certain circumstances that doing stuff in or around water alone increases risk of harm. There wouldn’t be anyone that could pull you from the water, do CPR, call an ambulance, protect you and try to keep you warm.
It doesn’t matter if you’ve done it a hundred times, there is always a risk.
The medical professional should be consulted before engaging in a new or vastly different exercise program. Medical professionals can identify preexisting conditions and use family history to help design the exercise program.
Either let them know you are there or check your blind spots
