I find contentment when my heart rate hits 160 – 85% of my heart rate max. My brain clears of thought. My awareness of “me” disintegrates. It feels really good to work that hard – mindlessly working and loving it!

85% is right around my lactate threshold – the point at which the body produces lactate FASTER than it can clear it. When my heart rate goes above 85% I begin to tire. The length of time I can spend above 85% depends on how hard I am working – I can build to 92% but need to shut it down immediately or I could stay at 88% for 45 seconds. My tolerance to repeat intervals above 85% is dependent upon the intensity of the efforts – I may have the capacity for 4 92% efforts or 10 88% efforts.

My long-term recovery is also impacted by amount of time I spend above 85%. I haven’t figured all of it out yet, but the more time spent above 85% the less likely I am to be able to reach 85% on the next attempt. I notice this more in the summer when I ride more. Some days my body just can’t work hard enough to get anywhere near 85%. When this happens I need to take a few days off from riding and allow my body to recover. This can happen even when my leg muscles feel fine; just as I can push my heart rate above 85% when my legs are still sore from specific leg training.

Regardless, it feels amazing to be working right on the threshold of exhaustion. It’s both mental tough and mental rewarding. Tough in that I can work harder and longer than my internal monologue believes I can and rewarding because I reach a point where the internal monologue stops and my body functions uninhibited by thought.