Hi Obinna,
Using the scheduling feature in BO is your best here.
You can schedule your reports to run early morning so that the employees will have the updated report first thing when they reach office.
Refer the admin guide for details on setting up scheduling:
http://help.sap.com/businessobject/product_guides/sbo41/en/sbo41sp4_bip_admin_en.pdf
However, to better your system performance you can also refer to the solution provided in the following thread:
Hope this helps.
Thanks,
Nagendra