Hello and welcome to MedHelp's forums. So, have you recently had your blood sodium level checked and found it to be low? How low is it? When is your follow up appointment with your doctor to go over the results and get a plan of action? The issue of sweating profusely after walking 3 miles with a backpack could decrease sodium levels at that time but that is an acute situation. You have the low sodium months later so I think your doctor will probably try to analyze why it is happening now as it is unlikely to be related to the backpack and walking experience. Things that can cause chronic low blood sodium are kidney issues, congestive heart failure, and various other conditions. So, please follow up with your doctor for your next step to uncover why your blood sodium level is lower than it should be. By the way, what is your age? Here is some information to review https://www.medicinenet.com/hyponatremia/article.htm. Please let us know how you are doing.
Hello~I agree with Sara, you need to see you doctor had have a blood test for sodium levels. There are many things that can cause it, you need to rule them out and then carry out a plan of action.
Mag58m thanks for stopping back. Can you give us any information? Are they concerned and looking for the underlying cause for low sodium levels? It would be important to investigate this. Let us know your next step.