A.M. Warm with a light wind, 12°C/53°F for a long run. Started well enough, faded in the middle and then funny enough after the long hill ascent I felt better and picked up again. Total 36k in 2:52:16, av pace 4:47/k, 7:42/mi.
In my running magazine I read a good article about the role of Natrium in endurance sport. I sweat a lot when I run but have never calculated how much until today.
The formula given is: Sweatrate (l/h) = [(Weight after the run – amount drunk in liters) – Weight before the run] / running time (min) x 60 min.
So for me I weighed 68,5 kg before the run. 66,1 kg after the run, (I was surprised, I checked 3 times, it is right) I took 4 small water bottles in my bumbag, each holds 125ml which makes 0.5l drunk in 172 mins.
My sweatrate today then was: [(66,1 – 0.5) – 68,5] / 172 x 60 = -1.01 l/h.
A liter per hour seems to me a considerable amount for the conditions today. Last May I ran a hill marathon and it was unexpectedly hot, in the 80’s (F). I walked at every water stop, drank and poured water over my head, but despite this at the end I was dizzy, felt nauseous and suffered from cramps, crawling in over the last few k and loosing 4 places. It’s an interesting problem to solve. | 