In my case, the cramping I experienced was minimal until the last day and then it was in my hands (think joints of your little fingers trying to join up to the joints in your thumb).  But I'd attribute that mostly to a tough 6 hour paddle into the wind (I think if we'd delayed our start for another hour, we would had declared ourselves wind bound for the day).

My paddling partner was worried that I was having a cardiac issue, so I did make a trip to my cardiologist after the trip.   According to him, I've had no cardio changes since my last visit (good news!). 

So I'm left with one of two possibilities (or a combination of the two) which dehydration or the results of a medication I don't usually take that I ramped up on during the trip (it helps to reduce the impact of tremors in my hands which tends to make my photography blurry). 

I do know that mid-trip I was dehydrated because my urine output was very dark compared to normal.  Luckily this occurred during an extended layover during the hottest days of the trip (well over 90 degrees on those days) and I immediately started to consume more liquid.  Before getting back into portage mode, my urine had returned to its normal color.  However, during that work period, I wasn't urinating very often, despite massive liquid intake.

The reason I think the medication could have taken on a role in this situation is that I only take it on a very sporadic basis, "as needed" because it tends to tank my blood pressure.  And, when my blood pressure is low, I tend to feel tired and sometimes dizzy.  I stopped taking it at the end of the trip, but when I got home my blood pressure was very low for me.  I'm typically "high-normal" and 96/52 NEVER happens. 

I'm guessing I set myself up for a "perfect storm" with the weather conditions, dehydration, and medication; and paid the price for it.  Being the last portaging day of the trip, we were lightly loaded and most of the portages were either reasonably level or more down hill than up.  I say lightly loaded because we didn't even have the evening meal or last day's food in our packs ... it was cached on one of the last portages going out.

But, it did leave an impression and I'll not be doing THAT again!

dd