Why do my legs buckle when i am tired? worse on awalening. see my med history pls. i am 49. wt 160 ht 64in, work on my feet 9hrs day

Working too hard: Your bmi likely is above 30. Excess weight will put more pressure on your extremities and back causing pain. Losing weight would definitely help. Have a comprehensive blood work to include test for sugar lipids and tsh, ekg etc go see your dr for a comprehensive check up.Take care!

Buckling: Can be a result of overuse syndrome you also may have a tight calf muscle complex, the muscles behind the legs are very powerful and can cause the knees to not straighten fully when there is a natural build up of Lactic Acid combined with the tight calf muscles. Dynamic and static stretch exercises may help quite a bit and the use of orthosis in the shoes can add to your comfort.