 [ Symptoms ] i had acl surgery 20 years ago intense rehab now in winter my knee swells and stiffens what is going on in my knee  i live in canada but have been escaping the winter in the past 7 years until this year after shoveling snow through the winter my knee kept getting stiffer and swelling occurred difficulty bending the knee getting up or sitting down it seems cold related but i may be wrong in the past 2 decades my knee did swell and stiffened after major exertions for a short time but very brief and not as intense as this time i am presently 47 years of age sincerely  stephen [ Disease ] ideally whether or not you have asthma exercise should be performed four to five times per week for at least 30 minutes talk to your doctor to find out how much exercise you should get