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.
Can you give us a more useful understanding of how many pageviews your site actually had? You only have three webpages. If we assume that for each visit the user visited all three of them and then further reloaded your home page twenty times, that's still fewer than one pageview per second.
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.)
