Hi ​@Metcalf24,

I see you've posted this a while ago. If you haven't found it yet - this is how (in the mobile app):

• open someone else's activity map
• (note: you might need to drag the activity details down to see all buttons on the map)
• in the top right corner, tap the Layers button
• in Heatmaps, select Personal

Note: make sure that you haven't enabled some specific filter for the Personal heatmaps. To check / correct it, go to the tab Maps > Layers button > Heat: Personal > tap the Edit button that appears under Personal > adjust as needed. 

I don’t believe ​@Jana_S ‘s solution will work in every case.

I think it is silly that when you just look at the map you can select to see all modes on both desktop and mobile but as soon as you go to create a route on desktop or view someone else's activity on mobile it will only show the heat of the activity type you are creating or viewing. For instance if I view a hike of yours I can't view my running heat map to see if I've been in the same area. This seems flawed.

And viewing anyone's activity on desktop there is no option to turn on any heat maps, global or personal. The inconsistency of the heatmap across devices is maddening!