Actually, I was thinking about water retention due to injury in general, but I suppose the same applies there. My weight went up by 1.2lb the day after the incident (not sure if it counts as an injury; not sure what it counts as, really), then down 0.4 from that the next day, and now it's down another 0.8 this morning. So while I'm still not back to where I was before it happened, it looks like I will be in a day or so.

ME/CFIDS being the fun and funky condition that it is, I'll be curious to see whether anything else sets off this reaction. So far the only other noticeable thing I've had was a 2.1lb drop the day after a nasty shock, during which I didn't eat as much, and over a week of intense stress. My weight bounced back up after that, though, and then plateaued (plateau'd?) for a week over my period, and then went back to falling. With all of that happening, my weight is now where it was on the day of that big drop 17 days ago, though if you discount that one-off day I'm still showing a pattern of loss overall.

How are your burns healing up?

Yeah, it would apply even more to other injuries, because there's less difference between a mild sunburn and a super bad one than there is in the wide scope of all other injuries. I mean, sure there's a HUGE difference between a little pinkness on the face and a full body, second degree sunburn with large blisters over 70% of your body along with dehydration (a sunburn that bad can be fatal), but when you look at other injuries the difference is even greater - from papercut to third degree burns over 90% of the body to an industrial or severe automobile accidnet.

I would doubt very much that you'd get any measurable water retention from a papercut, but beyond that "how much" and "how long" I would think are pretty hard to estimate.

I'm sure it also varies tremendously from individual to individual, and even for a particular individual (if you sprain your ankle ten times in your life, how much and how long you retain water could be different each time).

Stress itself is an "injury" in that it causes the body to produce stress-hormones/steroids such as cortisol.

I have FMS and possibly CFIDS (I was diagnosed with the fibro first, even though extreme fatigue and cognitive impairment were my most life-altering symptoms. When I was diagnosed, it wasn't unusual for me to sleep 20 of 24 hours. Before I had to quit working, my husband would have to drive me to work because I couldn't make the five minute drive without falling asleep. It would take me three hours to read emails that in the past I would do in 15 minutes). If I hadn't had a job that was largely unsupervised, I would have been fired at least a year before I quit.

Although I have my symptoms under much better control, I still have very random symptoms, including water retention. Whether it's the fibro/cfids or the autoimmune disease (I have an as-yet undiagnosed autoimmune disease attacking my cartilage and respiratory system. I have scarring on my lungs and it "ate" a hole in my septum (I could wear a nosering 3/4 inch in diameter if I were so inclined). I also have a very weird skin issue that is triggered by wheat, but other things as well (even when 100% wheat-free, I will get bouts of this). Hubby calls it "face-rot" which is actually fairly descriptive. It starts as redness and flaking and then if not treated with topical steroids, it will become raw, oozing open sores that crust over like impetigo (burns and itches so bad I want to claw my face off). And to clear THAT up, I need an infection or oral course of steroids.

As a result, I never know what "interesting" thing my body will do, and I never know how much of my weight on the scale is water retention. I can get a good idea by checking for pitting edema in my upper arm or lower leg (you press your finger into the flesh and it leaves an impression that doesn't immediately snap back), or I'll check the fit of my rings (my hands tend to swell if I'm retaining water).

Even when I can tell that I'm retaining water, it's impossible to guess how much. It's why I have to be very, very careful not to overeat as a frustration response to a gain on the scale (but really that applies to any dieter - eating in response to a gain, never helps).

I can't let it freak me out into drastically cutting calories either. I find that low-carb dieting seems to minimize water retention, so if I want to "check" for water retention, I'll often eat very low carb (my normal food plan is moderately low carb). Eating very low carb for a few days seems to help get rid of the water faster (although if you eat too low carb, then when you increase your carbs, some of that water comes back).

I've learned mostly not to focus too much energy on water retention. Or on "exact number" weight for that matter. If you get easily upset over small ups and downs on the scale, you can drive yourself absolutely mad-bonkers-crazy, especially if you have a body that retains water easily or unpredictably.

I have to just "trust the process" and know that if I stick to my food plan consistently, the fat and the extra water will come off eventually.

Reviving this thread, I'm now thinking about how painkillers can cause water retention. I've been noticing a pattern linked with taking codeine over the last week or so, and I haven't had any injuries, just standard headaches and muscular pain. On googling codeine and water retention, apparently it's not just me, quite a lot of other people experience water retention from various painkillers. Mind you, it could be tricky to work out where the water retention was caused by the painkiller, an injury if one was present (or something else causing inflammation), a change in eating/drinking pattern, or some other factor which I thought of a minute ago and now can't remember.

I recently have been having some dental problems and the dentist prescribed tylenol 3 (codeine) for the pain. I thought of this thread when I saw a gain that had to be water retention (I was barely eating at all because the pain of chewing was so great - but I also didn't go to the gym as usual).

I didn't even think of the codeine, but I have lost what I've gained now that I'm off the codeine, so that's a likely explanation.

It just goes to show you why you have to be very careful to avoid assuming the worst when the scale doesn't give us the feedback we want it to.