Routine provides a secure source of certainty. Pounding the pavement, treadmill or putting in long miles cycling, it's all good. It's all necessary. Getting away from the regular routine is a good break provided it's a short one and that you don't lose too much fitness while away. I am not good at getting quality rest. I know that and yet I don't do much about it.
I crash every now and then, not just on the bike! Severe strain and effort over time produce fatigue and weakness this can lead to the crash. Poor eating habits and lack of sleep will knock your fitness on it's behind. Ready to begin again? I think I am. And so it goes... enjoy it all!
