How do I persist and update Google's oauth 2.0 Token Access?

I have a Google Analytics account and need Token Access to make some requests that return data from my account. Whenever I use oauth to authenticate it works fine, however, when I change pages my Token data will disappear. I have already stored them in a $ _SESSION (php) to move to another page, and it works normally, however after 1 hour the Access Token expires and no longer works, and also does not update automatically even with the Refresh Token. Can someone help me? I have been unable to resolve this problem for some time.