Hey there! I had this question a long time ago as well, but it answered itself for me. When I started vaping I started on 36mg and used that for about 1 1/2 years. After a year of heavy vaping off of it my lungs felt 'weird' and hard to catch a breath occasionally. After I tuned it down to 24mg I had started feeling a lot better.No breathing quirks or anything, oddly 24mg never felt as though it was weaker also.
In my personal opinion I don't suggest friends to use 36mg liquids, but I don't believe there's any medical problem with the 36mgs, your body is just taking in a ton of nicotine and if you can handle that you can use it.