"The risks of non-fatal strangulation
There are many risks involved with choking during sex. Immediate risks include neck pain, difficulty breathing or swallowing, blurred vision or ringing in the ears, passing out, and loss of bladder or bowel control. After-effects include voice changes and speech problems, headaches, nausea and confusion, memory loss, long-term concentration difficulties, and in severe cases stroke or brain damage. When oxygen is restricted, people may experience disorientation and memory loss.
Repeated restriction can cause lasting cognitive issues, and in some cases strangulation can trigger life-threatening medical emergencies. If this happens, you should always call 999. "