To be able to finish an 820K, 22.000m increase, 7 periods contest, the only pace that will get you there corresponds to 2mmol (2 millimole) of blood lactate. This is a huge rate in general, but it is the rate you need to keep during all the long climbs, to be far more precise. In order to understand the tempo, you can figure it out having a laboratory or subject evaluation after which track it either using Watts (if you use a powermeter) or HR (your heart rate) as a professional cyclist.
It is strongly suggested because a powermeter the sole instrument that permits you to measure your external effort, that you just use it. Heart rate (which is an internal effort) tends to decrease after the first two to three days. Since the heart tires, it may make you underestimate your pace.
With all that in your mind, let us consider 2mmol is the rate that is perfect.
At 2mmol, on average, the human body works on the mix of 60% CHO (carbohydrates) and 40% body fat.
It’s significant that the body fuels itself on body fat as opposed to glycogen because there’s not enough glycogen to keep you running optimally. (The amount of glycogen stored in the muscles of most trained athletes is about 600 gr., corresponding to 2.400Kcal.)
It takes at least two days to recover correctly when you consume all your glycogen. Obviously nobody has time for that; the next stage starts in 18/20 hours.