Intermittent Claudication & Calf Cramps
Intermittent claudication is a disorder of an artery that causes muscle pain and is particularly common in the calf muscle group.This problem has a lot in common with angina pain in the chest. The heart and the calf are both big muscles that use a lot of oxygen to perform their jobs. To get the oxygen, they rely on it being carried by blood flowing to them via arteries. If the arteries are narrowed, the amount of blood available may not be enough to supply the oxygen that is needed to perform more demanding tasks. As you can probably imagine, your heart can’t just stop to have a rest if there isn’t enough oxygen. There is a way that your heart can continue to work without oxygen, but it produces a chemical called lactic acid that causes pain – this is angina. In your leg, you can consciously choose to stop the muscle working by sitting down. With the reduction in demand the blood and oxygen can come in and clear up this oxygen ‘debt’, eliminating the lactic acid. Everything gets back to normal and you can start to walk again after a few minutes.
Claudication can be confused with ordinary over-use type muscular pain in the calf but has several notable differences.
Normal muscular calf pain will usually involve stiffness first thing in the morning, pain walking up or down stairs and, when it is already stirred up, stopping to rest for a moment will not stop the pain from reoccurring as soon as you start to walk again.
Claudication pain won’t have an affect on your first steps of the day. Walking downstairs won’t usually be painful but walking upstairs usually will be after a certain minimum effort. When walking a certain distance (maybe 100m or 2 minutes) your calf pain will be brought on and you will be forced to sit and rest for a couple of minutes. You will then be able to start off without immediate pain and go approximately the same distance again before the pain returns. This is called your ‘claudication distance’ and you will have already found that it is reasonably constant over the same sort of terrain. It will happen sooner if the work is harder e.g. carrying heavy bags or going uphill.
Fortunately, while angina can be a precursor to heart attacks, which means heart tissue dying, this doesn’t happen in the leg. The calf muscle won’t die off, you will just be forced to rest because of the painful cramps. Some care needs to be taken with the foot as its blood supply will almost always be worse than the leg’s but painful symptoms don’t usually occur in the foot as the oxygen load required by the smaller muscles is so much less. If you have intermittent claudication, it is important to have the blood flow to the foot assessed so that you know if any special precautions need to be taken to avoid damage to the feet.
To read this Q&A session as a single handbook, or to access the downloadable / printable version, please browse to our Intermittent Claudication Info Sheet. Alternatively, use this link to return to the Podiatry FAQs Blog.