What does it mean if while someone is walking they get dizzy and their legs get weak and they feel like there is a black cloud blocking their vision?

Answer 1

It's a big chance it's Hypoglycemia (low blood sugar). When this happens the brain does not get enough glucose (a carbohydrate) and it is forced to prioritize. It uses less energy to make your muscles move and there's a big chance the brain will give the vision and hearing a low priority, which disturbs the balance and makes you dizzy.

This often affects you if you're having problem with your insulin.

Ex. If you eat a lot of candy your body will start to produce big amounts of the hormone insulin which lowers the blood sugar level (the candy contains a lot of fast carbohydrates which makes your blood sugar level too high) unfortunately the fast carbohydrates doesn't last long. The body will keep producing insulin and instead make your blood sugar level too low.

On the other hand this condition is most common among people with Diabetes who's already having problems with their insulin production.