It was a cut back week for the ERC marathon training group so only a 6 miler scheduled. Very mixed results. We started at 6 a.m. It was overcast but the humidity was near 80% and the dewpoint was at 67. I totally miscalculated the effects of the humidity & lack of sun and ran the first 3 miles about 15-30 seconds too fast for the conditions. From mile 3.1 there is a steady climb at a moderate upgrade for just over a mile. By the middle of the climb the too fast start caught up with me as my legs started feeling heavy & I was feeling overheated and slightly nauseous. I hydrated at 4.1, but still felt bad when I restarted so I walked just short of a half mile. At that point I had cooled down and my legs felt better so I decided to run it back to the finish. I actually felt pretty good on this last stretch and was able to finish the last 1.28 miles strongly, running pretty much the way I had started. Anyway, lesson learned. I definitely need to monitor pace more carefully early in these longer runs when the dewpoint gets into the upper 60s even when the sun & excessively high temperatures are not a factor.