What is the Sign of Pre Diabetic Condition

These patches may occur anywhere, but are usually seen around the neck, in the armpit, around the groin and sometimes in other skin folds. 

Other than a pre cancerous sign , in most cases it's  a sign of an underlying problem or condition such as obesity, diabetes or abnormal hormone levels. 

Acanthosis nigricans is usually the result of obesity. This is known as obesity-associated acanthosis nigricans.

It occurs because obesity can cause insulin resistance (when the body is unable to properly use the hormone insulin), which may lead to high levels of insulin in the blood, affecting the skin cells.

Insulin resistance can also cause type 2 diabetes, so acanthosis nigricans can be an early sign that you have diabetes or are at risk of developing .

To prevent insulin resistance, exercise always helps

What is the best exercise to prevent insulin resistance?

A long walk.