That depends on where the heat might be coming from.
Does the heat from the sun or the air temperature get to you sometimes? Or environmental heat from your workplace or home? Perhaps your body itself has a tendency to make too much heat.
What kinds of heat can come from emotions and mental activity?
Think about what might heat you up too much, but don’t write about that. Write about your strategies for preventing that from happening.
Add decoration to the page. Maybe you want to draw a little before you write. Or alternate between writing and drawing.
When the page is full, be sure to give it a title and write the date on it, too.