It’s like smoking. If you take identical twins and one smokes but the other doesn’t, the smoker is going to end up with a significantly higher white cell count. In Japan, for example, as smoking rates have steadily dropped, so has the normal white count range, such that about 8% of never smoking men would now be flagged as having abnormally low white counts if you used a cutoff like 4. But, that’s because most people were smoking before, when they set that cutoff. So, maybe 3 would be a better lower limit. The inflammation caused by smoking may actually be one of the reasons cigarettes increase the risk of heart attacks, strokes, and other inflammatory diseases. So, do people who have lower white counts have less heart disease, cancer, and overall mortality? Yes, yes, and yes. People with lower white blood cell counts live longer. “Even within the normal range,” every one point drop may be associated with a 20% drop in the risk of premature death.
Thank you Ted Huthchinson for your information. I will bear this in mind. I swim because I did competitively as a youngster and can still do it efficiently which helps lungs and general fitness. I would be unable to walk with a backpack as my lower back would ache too much. I also have multiple levels of arthritis in feet and ankles and tarsal tunnel problems that are in and out of normal levels. (Have reduced weight carried in my bag as well.) I stand and mess around most of the day, because my GP said standing was enough. I also garden, not daily. Housework and so on. I am quite a busy bee on a daily basis.
But many thanks for the information on Vit D