Brief Answer:
Narrowing in the spine, narrowing in the arteries

Detailed Answer:
Hi,

Thanks for your question and I'm sorry to hear about your symptoms.

There are a number of reasons why your legs might feel heavy when walking. If you also have pain in your legs we call this intermittant claudication.

Narrowing in your lower back called spinal stenosis can cause these symptoms. This is diagnosed on an MRI scan.

Clogging of the arteries in your legs can cause such symtpoms. Examining your pulses physically as well as an arteriogram can show if there are any issues.

Varicose veins can make legs feel like this also. Compression stockings can help with these or surgery to treat the veins.

There is another condition related to your diabetes than can cause the feeling of heaviness in your legs and this is a peripheral neuropathy, or diabetic amyotrophy.

If you are also feeling run down and tired then it would be important for you doctor to perform a full physical assessment and take some blood to check to make sure that you are not anaemic, that you liver and kidneys are functioning well, that your thyroid gland is working normally.

I note you have also had bypass surgery and so it would be important to check on physical exam and by an echocardiogram that your heart is functioning well as these syptoms can be a sign of a weakening heart that we call heart failure and you may require some changes to your medication to address this.

I hope this answers your question, I would encourage you to make an appointment with your family Dr to have some these issues addressed.

Best wishes

---