Exercise is very personal: the affect on your diabetes depends on the type of exercise, the length of exercise, your fitness at that exercise, your BG when starting and how much insulin you have on board.
I do a lot of exercise, try not to start with a BG higher than 8 or lower than 5 and find
- running for 20 minutes reduces my BG
- climbing for 90 minutes increases my BG
- walking for 4 hours makes no difference.
If you do not normally walk, it is likely to reduce your BG. Give it a go and find out.
Expect the affect to change if you do the same thing every day as you get fitter.