Position/order for "Low", "Medium", "High" options

Is there any convention about positions/order to display options buttons/radio- buttons/checkboxes for values as:

"Very low","Low", "Medium", "High", "Very High"

for attributes as Impact, Risk, Weight,....

would it be valid in the opposite direction?

"Very High","High", "Medium","Low", "Very Low"

For me it seems more common to see "Low" on the left and "High" on the right. But i woulds like to know it is a convention or it depends on its positive/negative connotation.