Wednesday, 5 August 2009

Circadian cycles?

On Tuesday morning I hauled myself out of bed at 5.50am to do a ten mile run with five miles at tempo pace. I knew all was not well when my heart rate was in the early 150s after a very slow first mile warm up. Upon beginning the tempo pace section of the run I was huffing and puffing within quarter of a mile and I was scarcely making marathon pace! After four 'tempo' miles with a split average of 06:56 I 'bonked' on the fifth. I felt shattered and shuffled back home feeling miserable.
Reviewing the run information revealed an average heart of 166 during the tempo miles, which is quite high. However, it actually felt higher and the effort felt more like 10K than half-marathon effort.
A brief google search on 'morning running tips' revealed the following article from Running Times on 'circadian cycles'.
In short, it would appear that for most people, the early morning is the worst time to engage in vigorous physical exercise. Interesting article and I intend to hang onto this as an explanation for my rotten performance. My next tempo session, which will take place in the evening, should provide 'the litmus test' for this assertion.

1 comment:

PJ Carroll said...

Just noticed your blog...Wish you all the best in your marathon training.....Early morning tempos are a disaster, potential injury as your body is insuffiently warmed up. I would think early Morning time is good for easy (8.50 mile pace approx recovery runs).
The kenyan elites run their first morning mile at maybe 9 min pace.