I've always had difficulty regulating my blood sugar during the Spring. In an effort to find context around this anomalous season, I've plotted all my glucose readings during the "red" pollen days (pollen count of 400+) in Atlanta for 2012.
For the first 11 days, my glucose stays in a controlled range. Towards day 12 and beyond, you will notice some sharp spikes and dips. After looking at the numbers for 2013, I found this trend to be consistent. Digging further in, I discovered that while the heaviest of the pollen counts might result in congestion, the later days pose more of an allergic risk from pollen-producing trees like walnut and pecan.