Most Heart Attacks Happen Below the Knee
I was sitting in a session at a diabetes conference when the speaker said something that made the whole room go quiet.
"Most heart attacks happen below the knee."
Your heart is not in your foot, so on its face the statement makes no sense. But it is one of the more useful reframes I have heard in years, and it matters more for people living with type 2 diabetes than for almost anyone else.
The disease is not in your heart. It is in your arteries.
Atherosclerosis is the process where plaque builds up inside artery walls and narrows them. We talk about it as a heart problem because that is where it makes headlines and kills people fastest. But it was never a heart disease. It is an artery disease that becomes very dangerous when it reaches the heart.
The same plaque narrowing an artery in your chest is narrowing the arteries in your legs, your neck, and your kidneys. It is one process happening everywhere at once, at slightly different speeds in different places.
When it closes off an artery in the heart, we call it a heart attack. When it closes off an artery in the foot, we call it peripheral arterial disease, or a wound that will not heal, or in the worst outcomes, an amputation. Same disease. Different address.
The point that speaker was making was about timing. The earliest evidence you can actually see and examine very often turns up in the feet, long before anyone has chest pain.
Why diabetes puts it below the knee
Peripheral arterial disease does not distribute itself evenly. In people whose main risk factor is smoking, the narrowing tends to appear higher in the leg. In people with long-standing type 2 diabetes, especially alongside kidney disease, the pattern shifts downward into the smaller arteries below the knee. Those vessels have fewer alternate routes around a blockage, they are harder to open surgically, and they supply the tissue farthest from your heart with the least margin for error.
Then there is the part that makes this genuinely dangerous rather than merely serious. The classic warning sign of poor circulation is claudication, a cramping ache in the calf that shows up when you walk and eases when you stop. It is annoying, limiting, and extremely useful, because it sends people to the doctor. Diabetes can take that signal away. When nerve changes affect the feet and lower legs, the message never gets delivered. The circulation is compromised and the person feels nothing at all.
This is why so many people are shocked to learn their circulation is poor. They were not ignoring symptoms. They never had any.
What it actually looks like
The version I see most often is not dramatic. Someone breaks in new shoes and gets a small blister on the side of a toe. It does not hurt, because sensation in that foot is already dulled, so it barely registers. Three weeks later it is still open and now there is drainage.
That blister was never a shoe problem. A foot with good blood flow closes a blister in a week without help. One that stays open for three weeks is telling you the tissue does not have the blood supply it needs to do basic repair work.
It is also not only a foot finding. Someone with documented peripheral arterial disease carries a risk of heart attack and stroke in the same range as someone who has already had a coronary event. The foot is the messenger. The message is about the whole system.
The two minute foot check
Sit somewhere with good light where you can reach both feet. Look at the tops, the bottoms, the heels, and between every toe. If bending is difficult, put a mirror on the floor, use your phone camera, or ask someone in the house to look for you.
You are looking for:
Any sore, blister, callus, or crack that has not healed within two weeks
One foot that feels noticeably colder than the other
Color that differs between the two feet, especially pale when you raise the leg or dark red when you let it hang down
Shiny or tight-looking skin, hair loss on the toes and lower legs, or toenails that have nearly stopped growing
Numbness, burning, tingling, or pins and needles
Cramping in the calf that comes on with walking and eases with rest
Swelling on one side only
Compare your two feet against each other. A difference between sides is often more informative than the finding itself. Do this the same day every week so it becomes routine rather than something you remember only when you are already worried.
How to ask for a PAD screen
If you find something, do not wait for your annual visit, and use the actual name of the thing you want. Asking by name moves you from mentioning a symptom in passing to requesting a specific evaluation, and those two things get handled very differently.
One more piece is worth knowing. The standard screening test is the ankle-brachial index, or ABI, which compares blood pressure at your ankle to blood pressure in your arm. In people with long-standing diabetes or kidney disease, the leg arteries can stiffen in a way that resists compression, pushing the reading into the normal or even high range while circulation is genuinely poor. A toe pressure gets around that, because the small arteries in the toes are usually spared.
You do not need to memorize the physiology. You need one sentence:
"I have diabetes. I want a PAD screen, and I want to know whether my ABI will be reliable or whether I need toe pressures."
That question tends to get you taken seriously.
What I want you to walk away with
To be clear about the limits here, a cold foot on a cold morning is not peripheral arterial disease, and most of what you notice during a foot check will turn out to be ordinary. The point of checking weekly is not to generate anxiety. It is to build a baseline for your own feet, so that when something genuinely changes you catch it in week one instead of week twelve.
Foot care gets filed under housekeeping, somewhere below medication and food on the list of things that feel like they matter. It belongs much closer to the top. Looking at your feet is one of the very few ways you can observe what is happening inside your circulation without a lab, a scan, or an appointment.
Take your socks off tonight. Then ask for the screen at your next visit. That is the whole ask.
Russender Powell, MS, RD, LD, BC-ADM, CDCES, is a registered dietitian and board certified in advanced diabetes management. She works with people who want to understand what is actually happening in their bodies, not just what to eat.
This article is for education and does not replace an examination by your healthcare provider. If you have concerns about your feet or your circulation, contact your care team.
