Lots of people are misunderstanding that chartbeat figure. It's not 287 visits in a 45 minute window. These are visitors who are currently interacting with your site. Some are idle but most aren't.
As you had a spike to 282 concurrent visitors (four times your average), even under that unrealistic amount of reloading, that's less than four requests per second. (Again, really: one way to look at that figure is "in a 45 minute window"; I provide the broken-out math below to make it clearer.)