Hi All, just a quick question in regards to sweating whilst running. I worked out I currently lose 4lbs to sweat every hour, is this excessive and should I be concerned. I am training for Edinburgh Marathon and completed 19 mile twice at 2hrs 40 mins, I was absolutely saturate and weight loss was 10lb. So it is fairly accurate. I currently weigh 16st 8lb and just coming back from a Pulmonary Embolism, so I am having to work that little bit harder.