Hypothermia: i know when you're temp really drops you actually stop shivering, why is that and at what temp does that happen?

Below 35C or 95F: Shivering increases heat production by the body as much as 5 times normal metabolism. Normal body temp is 37C or 98.6F. If the temperature drops below 36C or 97F we start to shiver sooner if the rate of change is rapid. Below 35C blood is shunted away from the muscles and the periphery and metabolism slows in an attempt to preserve the vital organs in the core. The heart stops at about 30C 86F