Hi Welcome to.HCm
Dear , as you are fit and healthy , feel fine afterwards you run 3-4 m iles on the treadmill every week and set the resistance . you can carry on your regime .
High resistance training do affect the heart if you do it abruptly . If gradually you increase your targets it will help strengthen your heart as well as your whole body .
Consumsion of Diet including all essential nutrients -- fiber ,protiens
vitamins and minerals will further help high resistance .
Avoid processed foods carbs , sugar , fried ,fast foods , Tea , coffee ,alcohol and
smoking all will produce biochemical and metabolic conditions in your body that will decrease your immunity , so avoiding is definitely the first step in the right direction to detoxing the body, boosting the immune system .
Hope this helps solves your query .Take care .All the best .Get well soon
Don't hesitate to co m e back in case of any further query .