I'm suddenly sweating a lot.

I've never been sensitive to heat or sweat much before, but maybe because I'm getting older, I sweat quite a bit when I walk or hike, more than I used to. People say that sudden excessive sweating can indicate health issues, is that true? Of course, it might also be because it's been very hot lately, but since I suddenly sweat a lot, I'm a bit worried. Please give me some advice.