Exclude php from being cached

Thanks for this great plugin!

I have a question about excluding php from being cached. I’m using the code on this page https://docs.woothemes.com/document/show-cart-contents-total/ to show the cart subtotal in the header of my site.

When i add something to the cart it works but if i go to another page this code is cached by Zencache and ‘freezes’ when i add a new product to the cart. I would like to exclude this piece of code from the cache. Any idea how to solve this?

https://wordpress.org/plugins/zencache/