I recently got a blood test and I have a low white blood count. Here's the line from the test:
WBC . . . . . . . 3.2 L (3.6-10.6)
So, apparently the healthy range is 3.6-10.6, but I only have a 3.2. The doctor noted that this would leave me "susceptible to infection and colds". Well, since I haven't had a random infection or cold in... almost two years, this connection does not seem to be accurate. Yes, admittedly I've been mildly sick a couple times in the past couple years, but I know exactly why it happened. And even so, it wasn't anything like how I used to get sick, which was more often and much worse. Things just don't add up to doc's observation.
So, I'm not an expert on what tests like these mean, but here's my thinking. This "normal" range of 3.6-10.6 is based an averages collected from the general population. Not the healthy population only (people who live a long time and don't get sick), but everyone. So, what if the general population is not healthy? What if the general population actually gets sick a lot and depends on many drugs, stimulants, and fortified "foods" to keep them feeling ok? (Hint: this is the case)
Let's compare an athlete to a lethargic person. An athletic person who works out and trains consistently has a stronger body, and thus a stronger heart. Because of the heart's additional strength, it is much easier for it to pump blood during rest, and consequently it has a lower heart rate. In other words, the heart is able to move more blood on each pump, and so it doesn't need to pump as often. Also, the blood cells are able to carry more oxygen and so on. So this lower heart rate is actually a good thing. It means that the athlete's heart doesn't have to work as hard during rest time.
So, consider a hypothetical population entirely of lethargic and lazy people only. Their high heart rate would be considered "normal". And if one of these lethargic people had a lower heart rate than that standard, it would not be a good thing like in the case of an athlete. Indeed, for a sloth that lower heart rate would probably mean that something was wrong.
Then, lets say one tiny percentage of this previously lethargic population becomes active. The active people would become healthier and develop a lower heart rate, and the doctor would probably tell them that it is dangerously low! So what should they do? Either 1) take some drugs, or 2) go back to being lethargic. Both of these actions would get their numbers back to "normal", but neither of which is a necessary or correct solution!!
That's how I feel about my low WBC. I'm being compared to Joe Shmoe who eats a Standard American Diet (SAD), stressing his body on a regular basis and forcing it to react with in a defensive manner. However my body is clean, what does it need a bunch of extra white blood cells for? That's why I'm not getting sick, contrary to doc's prediction.
I could very well be wrong in this logic, since I don't really know much about human biology other than the simple cause-and-effect relationships of my actions and how those actions make me feel. But I do know that I'm not getting sick and I feel great. If you know something that I don't, leave a comment.