A gf of mine is a nurse and I asked her about this last week - I had done some heavy lifting with a new grip and wondered if I just stressed the hell out of my hands. I'm just going to keep it simple and give it to you exactly as she sent it to me, sans swears: "You're probably not taking in enough electrolytes. The imbalance in salt levels between cells, blood stream, and your extracellular spaces essentially results in trapping water in the tissues as the sodium is lost in sweat. The same thing can happen if you are taking in too much salt. The force from swinging your arms totally added to your Disney character hands." She said that anyone exercising or doing any activities in the heat needs up to 2.07 g of sodium per litre for proper recovery but that drinking it would be like drinking the ocean. So just to add some to my water and up the levels in my food the days I'm working out. Shazam! Food for thought for anyone who is interested. Now I have to make her ice cream.

Happens to me too. Just found this article [http://health.msn.com/health-topics/heart-and-cardiovascular/why-do-my-hands-swell-up-when-i-walk][1]

Just a little cutting and pasting based on Quilt's answer. This is all stolen from the interwebs - but I guess I better understand the need for sports drinks - sugar free of course.

Effect of exercise in the heat on plasma renin and aldosterone with either water or a potassium-rich electrolyte solution. Francis KT, MacGregor R 3rd. Abstract Information concerning the renin-angiotension-aldosterone system during physical exercise in the heat with adequate fluid and/or electrolyte supplement is lacking. The present study was intended to describe the changes in renin activity and serum aldosterone, serum sodium, and serum potassium in subjects receiving water or a potassium-rich electrolyte solution while exercising (50% VO2 max) for 120 min in a warm environment (32 degrees C, 50% relative humidity). This study shows that, in subjects receiving the electrolyte supplement, serum potassium is elevated slightly during the exercise period whereas serum sodium is unchanged from preexercise levels without the electrolyte supplement. Plasma renin and aldosterone levels were significantly reduced in the subjects receiving the electrolyte supplement compared to subjects receiving only water. The ingestion of the electrolyte supplement replaced 42% of the sodium and 100% of the potassium lost by way of sweat and urine while exercising in the heat.

Electrolyte recipe:

2 quarts of water 1 teaspoon of salt 1 teaspoon of baking soda ½ teaspoon of salt substitute (potassium salt

OR

1 cup (8 oz) water (not carbonated) 2 Tablespoons lemon juice small pinch of salt

I always thought that was a pretty normal reaction to high heat and humidity. Happens to me as well. I'd love to know why it happens also, though.

Notice any swelling in your ankles?

If so, probably a mild allergic reaction. Heat and exercise exacerbate them.

I stopped eating vegetables and the allergies went away. Dunno what might be the cause with you.

Also, I do better getting my electrolytes from scallops. Can't tolerate oysters for some reason.

Here's what the Harvard Doctor had to say in the link that Mary posted above.

What you are describing is common. It’s likely related to vasodilation, which means that blood vessels are opening up, leading to increased blood flow near the surface of the skin. Increased blood flow just under the skin makes the face pink or red and it may cause puffiness of the hands.

Contrary to popular belief, getting red in the face during exercise does not mean you are out of shape.

Vasodilation may occur as one of the body’s ways of regulating temperature. Releasing heat generated by exercise is important, as it allows the body to maintain normal temperature.

Even before working up a sweat (another means of releasing heat), the blood vessels near the skin tend to dilate. This allows more heat to be released from the blood as body temperature rises during exercise.

There may be other explanations for puffy hands during or after exercise:

An exaggerated, normal reflex. During exercise, blood flow to exercising muscles increases. In an effort to maintain circulation to other parts of the body (including the hands), blood vessels may dilate. In some people this reflex is more pronounced than others. Trapped fluid. During exercise, there is increased circulation throughout the body. While the legs have large muscles that work hard during many exercises and that help “pump” this added blood flow through the veins, the arms have smaller muscles and they may not be working as hard during a workout (for example, while jogging). If the hands are held below the level of the heart, the added fluid must travel against gravity. Together, these factors make it harder for the fluid to return to the heart. The extra fluid that is “trapped” in the hands can cause puffiness. Once you cool down and the circulation and blood vessels return to normal, your hands and the color of your face should return to normal. If your rings are tight after exercise, it’s probably a good idea to take them off before you start working out.

Your hand swelling and facial redness may be annoying but they are unlikely to be due to anything serious. Think of them as small prices to pay to stay in shape and avoid overheating.

here's the deal:

when it's hot, your body tries to cool you off by dilating the blood vessels in your skin. dilated blood vessels simultaneously make your skin look redder. (it does the opposite when you're cold, conserving your bodies heat by constricting the blood vessels.)

the thing about dilated blood vessels, however, is that more fluid and squeeze out of them into the tissue of your fingers and they get fat.

this happens to me all the time, too!

sounds a lot like the adrenal renin aldosterone system sending up a warning flare to me.