Q: 10.11.6 Macbook air keyboard and trackpad won't respond after long sleep

Hello

I have a MacBook air mid 2009 ,installed El Capitan Ver. 10.11.6 up to date

When I let the Mac for a long period of sleep without shut down the keyboard and trackpad won't respond.

the only way to be able to use it again is to make a hard reset and restart it again.

How can i fix that ?

If it just go to sleep for a short time all is fine ! .... I don't figure out this issue.

Thanks for your help.

Seb