Hello, Thanks for posting on HCM, Clot in lungs is medically known as pulmonary embolism and it is a very dangerous and life threatening condition that it is best not to follow medical directives. Exercises are good for health but not always when it involves some cardiovascular and lung diseases. Having clot in your lungs where the source can not directly be identified is not very good and it is best to keep intense exercise at low for a while before you get back into it. The clot if it breaks too fast into fragments can circulate into other small vessels which can lead to severe respiratory distress hence death. Now blood thinners are to be used with caution given that you have bleeding ulcer as this can also cause more bleeding. If you do exercise and cause blood to pump too fast (given your two medical conditions), the result could prove fatal. It is best to allow sometime for yourself to heal fully then you could then start exercising gradually. Also, pulmonary embolism is a risk factor of stroke. I believe your doctor has you at heart when advising to stay away from exercises for 1 month. Hope this helps and wish you the best