My legs are giving up on me

I have incredibly weak legs. Over the last year or so it has gotten progressively worse. I cannot complete a simple squat (can't get back up), cannot do lunges, and can barely walk up a few stairs without having to stop. It is NOT shortness of breath. I am a newly 40 year old female and appear to be in decent health. I am afraid. I see elderly, extremely obese persons, handicapped persons, climb up stairs. What happened?

[yellowbean]

There are a whole host of things that could cause the symptoms that you describe.  Any one or none of these may apply to you.

1) Spinal stenosis, this can compress the spine which cuts off the nerves that feed the muscles to the legs.  This can result in muscle atrophy (shrinkage) and weakness.
2) Neural Foraminal Stenosis - Similar to spinal stenosis, but typically produces symptoms on one side or any other, but one side greater than another.
3) Neurodegenerative disorders - There's a whole bunch of these, far to many to go into.  
4) Primary problems of the muscles themselves - this is typically in kids, think Muscular Dystrophy
5) Strokes
6) Multiple Sclerosis
7) Vascular disorders - Atherosclerosis (Hardening of the arteries) not terribly likely given your age, and people usually have other symptoms such as rest pain, where you legs hurt at night and you have to hang them off the bed for relief.
8) Psychosomatic - It's all in your head.  Trust me on this, it happens...I experienced some very real symptoms in my life that were completely in my head...The more we think about things, the more we interpret our normal bodies as abnormal.  Please don't take offense to me including this, but it is important to be complete.
9) Others

If you have not already, you need to be examined by a doctor that will then need to order tests.  These tests can differentiate different causes for you.

Some things they "May" order depending on what they find during the exam.
1) CT/MRI of the brain and/or spine.
2) Nerve conduction studies
3) Treadmill test to look at your heart.

Bottom line, go get examined, there is no other way to sort this out.

[SassyLassie]

If all else fails, then by all means see a good chiropractor, you could very well have some pinched nerves and that could definitely cause the problems you are describing.

[ku111]

Have you been to the dr.?  If you haven't please make an appointment.