What do you wear under your jearseys during a triathlon?

That entirely depends on the weather! I like to run feeling a bit cold to don't tend to wear much under my vest unless it is arctic! As soon as winter comes around then I usually switch to skins thermals or some kind of gore base later. What kind of running are you doing at the moment - cold or warm weather?

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Training Blog - Polar RCX3 Watch Review

Warm weather