Thank you for your query. I would like you to clarify a few things for me. 1) how old are you ? 2) are you a diabetic, hypertensive or have a history of high cholesterol and heart disease? 3) have you been diagnosed with any valvular or structural heart defect? 4) do you smoke or consume alcohol? 5) do you behave any joint pain or any problem with you skin, hair, and nails( like discolouration or dry or damaged) 6) do you have thyroid deficiencies? are you anemic your symptoms seem to result from a reduced blood flow to you extremities and that your heart is straining to meet the demands of your body while you exercise. the answers to the questions above in addition to a physical exam and blood tests will help to pinpoint a diagnosis. I would like to rule out heart disease and risk factors like diabetes , hypertension, dyslipidemia , hypothyroidism and any heart structural abnormality. You would need and Electrocardiogram, and Echocardiogram, a treadmill test ( after consulting with your physician and blood work for checking you kidney, liver thyroid functions and lipid and blood levels. I suggest you visit your physician right away and also get a cardiologist to see you. please do no strain yourself till we figure out what is going on. Subtle signs like this, especially when noticeable by you indicates that something is wrong. it is good that you picked up on it and sought advice. Do not, however wait for it to get worse to see a doctor. Hope this helps and please get back to us if you have further questions. wish you good health