In the Insight module you can use the scrub bar to view the last 6 hours of your events heat map.
It is possible to view much further back than that through the replayable, zoomable heatmap function in the Analytics module.
Ensure you are in the Analytics module and have the mapping (not the Charts) interface visible. In the left hand menu expand Heatmap to bring up the controls, by clicking the three dots alongside the Heatmap title.
Then enter the dates that you want to view (max 24 hours) and pick the time in minutes per frame of playback. The default here is 1 minute per frame. For example for 30 seconds per frame, change this to 0.5.
Once the heatmap data has loaded in your browser the heatmap will automatically replay.
Note this make take 30secs+, depending on the size of the data file requested and your connection speed.
You can then use the arrow in the bottom left to toggle the menu to access three controls for altering settings for how heatmap layer is rendered. Increase/decrease any of intensity, radius and blur to your own personal liking.
These settings will then persist for you.
Use the controls at the foot of the screen to pause/play, fast forward and rewind using the right of the two scrub bars and/or change the speed of playback, using the left of the two scrub bars.
You can also focus in, to a very granular level, on any specific location you might be interested in. Or alternatively focus out to widen the are of coverage.