in my opinion..as long as you work out when you ovulate it shouldnt be a problem,
i have/had a 31 day cycle.. i tried for a year when i fell pregnant (ectopic) fell pregnant 3 months later (blighted ovum) then couldnt fall pregnant.. after 5 months of testing my obgyn and i finally found out when i ovulated and i fell pregnant the next month!

i used the maybe baby saliva ovulation test, im not sure how others feel about it but i loved it

thats my opinion anyway.. good luck!