The Nevis breakfast, again
Finally needing a climbing rest day I went for another fasted run before breakfast. The weather was fine so I opted for Ben Nevis, straight up the slope from the Glen Nevis road end in a brutally steep glycogen burning continuous climb straight to the summit. Going as fast as I could, I could start to feel the glycogen tank emptying after only 45 minutes, motivation to keep slogging dying off and being replaced by a strong desire to lie down and sleep.
Having a few of these runs in the bag recently is meaning I can now keep going a fair bit better once the tank is empty and I’m making glucose out of body fat. The next 45 minutes to the summit felt predictably hard work, but some good tunes got me through it and all of a sudden strolling over the plateau to the observatory.
I sat down in the cool breeze among the crowd of summitteers, for a few minutes. I couldn’t stay though, I was pretty damn hungry and the sound of many sandwiches being munched all around me was deafening. Get moving!
My legs felt worked but were still strong to bounce back down the boulderfields in a good run and off into Coire Gubishean and onto to upper Steall. Running through Steall I could really feel I was burning fat and stopping running even for a moment to clamber over rocks on jelly legs gave me an overwhelming urge to lie down. So I cruised on happily down the familiar path back to my car and an egg roll in town.
Today, I’m 34. Birthday itinerary: Swimming with the girls, book writing, feeding midges at Steall.
We appear to have had matching birthdays: running, swimming (do you like swimming now??), and climbing! I hope the midges ended their evening still hungry and your project ended its evening slightly closer to victory...
ReplyDeleteHappy B-day Dave!
ReplyDeleteHappy birthday Mister Dave!
ReplyDeleteHappy Birthday Dave!
ReplyDeleteMy comment on glucose being made out of fat to fuel your running after glycogen depletion:
there is very little glucose to be had from fat (only the glycerol backbone can be turned into glucose, this process is very inefficient and not very relevant for high energy demands of running)
some glucose may be had by gluconeogenesis from lactate generated by glycolysis, but lactate is preferentially used by heart muscle as energy source during the run (if you can keep on running)and the liver for gluconeogenesis, both of these processes are oxygen-dependent (that's why you won't run your fastest without sufficient muscle glycogen stores)
the real metabolic source of energy coming from fat when you're running on empty are ketone bodies; the ability to generate these from fat and then oxidise them in mitochondria is the physiological characteristic that has to be trained to allow humans to run on empty glycogen tank and survive prolonged starvation ( I recommend Cahill's paper 'Fuel metabolism in starvation', I found it very revealing )
All the best on your Steall project, your efforts on it are inspirational!
Pete
happy B-day máquina, keep inspiring us...
ReplyDeleteHappy Birthday Dave!
ReplyDeleteHappy Belated Berfday Dave! Keep up the good work!
ReplyDeleteHappy birthday for last week mate - same day as me! Sounds like you had a nicer day of it. Keep up the inspirational work!
ReplyDeleteHappy Birthday Dave - have a great one ! Love reading the blog, thanks for all your hard work.
ReplyDelete