FWIW, here is my lay person's take on what is being spoken to here. Basically, we all have our own unique "ledger" or health balance sheet, accumulations of positives and negatives that apply to our overall condition of health. For many reasons, some good, some not so good, most of us are never really fully aware and or informed as to what our own individual health balances are.  Flechas, Brownstein and the other familiar Iodine researchers themselves have mentioned, repeatedly, that the older a person is before first beginning Iodine supplementation, the better the chances are tha they have - in many cases unbeknownst to themselves, situations/processes going on inside their body's as a cumulative result of time / habits / lifestyle / diet; undiagnosed hypothyroidism among them, as are potentially undiagnosed this, that and the other. Think of anything that erodes over time.... the more time erosion has to wear away at things, the worse the crumbling and wearing away effects, bit by bit, will be. To one extent or another we all can sort of relate to how the process of getting older in large part involves us adapting to the fact that our body's are slowly degrading, as each day/month/year passes we get accustomed to how various of the many inner-working parts/functions of our body no longer function they way they did because they are slowly dieing off, and to a real extent, we all have sort of become programmed/conditioned to be complacent to this situation. There are no rules, for some people these effects may start to be noticable at a relatively young age - perhaps mid 30s, 40s, 50s.......whenever. Some people have slowly failing senses, like sight, hearing, cognitive function, tactile/feeling senses, the who nine yards. Some people grow all kinds of weird attachments to their body - skin lesions, boils, tags, blemishes, corns, ingrown nails, going bald....whatever. There are no hard & fast rules except that by and large we each get to experience our own personal way of having our bodys & bodily fucntions degrade (slowly dieing off)  before our own very eyes. What Ford is saying is that as one begins to supplement with Iodine, it (Iodine) begins to effect whatever internal processes for which it can be a benefit..... kinda think of this as like starting to make regular payments against a long-standing, massive debt that has accumulated..... there may be some shock.... and actual tingling, involved with such an endeavor. One of the reasons that any part of our body/body function becomes lessened is due to nerve damage and or nerve tissue becoming dead OR severely retarded. Iodne, potentially, may be able to reverse some of this.... and one may need to go through weeks.... or months.... or maybe even years of "tingling" sensations during the process of these formerly degraded functions springing back to life...... part of the price one may have to pay if they want to regain some particular health.