我的会话变量在一段时间后失去了它们的值，我可以以某种方式延长这段时间吗？

My session variables hold the values that the users use to log in but they seem to initialise after five minutes or so if the website isn't used. Is there any way I can lengthen this period as the system logs the user out if the log in details are not there?My session variables hold the values that the u