Voice Issue - always bugged me, but now I want to know

Hi

I am in my late 30s, and as far as I can remember, I always had issue with my voice going low. My normal voice is deep, but when I miss a meal or concentrating hard on some issue at work, my voice goes really low. Like yesterday I went to gym in the morning before having any breakfast, I felt fine even after the workout, but my voice gradually went down in course of the afternoon and stay that way until the next day.

Does anybody know or understand this?

Thanks
Vijay Tweet