Moderately hard exercise lowers blood glucose after a couple of hours. But really tough and hard training can work the other way around and raise the glucose!

The effect of a walk can significantly lower blood glucose for about 12 hours. So, in order to have a stable effect of lowering glucose, you need moderate exercise every day.

But if you for example run as fast as you can, blood glucose often rises after exercise due to all the stress hormones that are released when you exhaust yourself.