Quite a few men on the Peak Testosterone Forum have complained of a low body temperature. The general assumption is that men with low body temperature have “adrenal fatigue” or hypothyroidism. What few men (and perhaps physicians) realize is that recent research has shown that too much salt will also lower body temperature and may explain at least a part of their issue.
More importantly, what researchers have discovered is that it is this decrease in body temperature that is the root cause for salt sensitive hypertension. I recently found out that I was salt sensitive and that it is quite common: estimates that I have seen are around a fifth of the general population.  I tell the story as to how I dropped by blood pressure by 10-15 points by eliminiating extra added amounts in my diet on this page: Salt Caused My Prehypertension.
To understand what is happening salt sensitive people like myself, you have to realize what happens when you ingest a bunch of added salt. Salt, after all, is not something that Paleo man ran across nor his hominid ancestors before that. The body basically says, “What in the heck is all this salt?” It finds itself going through the following metabolic roller coaster:
b) Your arteries initially will dilate in order to handle the extra volume of water entering your cardiovascular system.
c) Heat loss then increases and body temperature will start to fall due a) and b).
This is when it gets interesting, especially for salt sensitive individuals. Salt sensitive individuals experience a greater drop in body temperature and then the following happens:
RESEARCH: A recent study gave strong evidence that this was really the case and to test their theory gave salt sensitive individuals and controls 11 grams of salt. It was spread out in short intervals but was given pretty much all at once. 
Of course, this is a LOT of salt. However, it is not completely off the rails considering that the typical American consume 3.4 grams per day on average. (Many of us consume significantly more.) They went on the high side, though, to prove a point:
What they found was what I stated above: salt sensitive people had a significantly greater loss in body temperature that the non-salt sensitive folks verifying the ideas presented in a) through d) above.
I would add that the average lowering of body temperature was close to a degree (Fahrenheit) with that 11 grams of salt. So, if you are 2 degrees below 98.6, I doubt that salt coupled with salt sensitivity explains it. However, we should all keep in mind that excess salt could be playing a partial role in lower body temperature. And, regardless, what is the point in shoving a bunch of extra water into your arteries?!
CAUTION: Let me just mention that I recognize that athletes need more salt and also that extra salt does not seem to affect most men in the general population. However, for those of you that are salt sensitive like me, reading this and some of my other pages on salt will be a godsend.
1) Diabetologia, 1995 Dec, 38(12):1443-8, “Increased prevalence of salt sensitivity of blood pressure in IDDM with and without microalbuminuria”
2) Hypertens Res, 2011 Jun, 34(6):753-7, “Effect of acute salt ingestion upon core temperature in healthy men”