When I am getting ready to show my horses, I use a neck sweat 24/7 - for two months. I also have an exericse regime, and specfic feed I feed them. I also change the way I wrap the necks when I work them. I can tell there necks are sweated after the first workout but want to keep nice like that, so they wear them all the time. (not the neck sweat I use for workout).
It is not just the neck sweat that makes them fit, it is combination of many factors. Good luck.
A sweat is usually lined with neoprene which holds in the heat and doesn't allow the skin to air out/cool off very much. A wrap is usually just heavy fleece. It keeps the neck hot but allows more air circulation. I think I need to get a neoprene sweat for MY waist line ;-)
I have used a wide variety of "sweats" on our insulin resistant mare with the heavy crest. The smallest and easiest to use (and often used on driving horses so they can tuck their noses in better) is a throatlatch sweat. Those are usually 2 - 4" wide with neoprene on the outside and fleece against the skin. Neck wraps have neoprene on one end with a long piece of fleece attached and also come in different sizes. You roll them up and put them on like a leg wrap, starting with the fleece and ending with the neoprene. They need to be wrapped pretty tight and you should tie the horse with the head up or level, not down, or you could get them too tight. If they slip when he puts his head down they are too loose. Most people pull the mane out from under them. I put neck wraps OVER the throatlatch sweat, overlapping them a bit. Both of these can be left on 24/7 although they should be removed and cleaned and to let the air circulate.
"Neck sweats" come in lined (with fleece) and unlined. The lined ones come in all sizes including almost full body armor! I have used the ones that just cover the neck which are also handy for protecting the mane. I have found them to be less effective than the wraps. These can be left on. The UNLINED neoprene sweats are for exercise time or brief use as they do not allow breathing. They can be used with sweating gels, which might be effective the week or so before the show. They cannot be left on for more than brief periods!!! Many people use plastic with neck sweats as it increases the heat but plastic can cause burns!!! I think if you stick with the lined kinds, do not use plastic, and keep them clean, you will find that your horses necks will improve and the horses won't hate you or be harmed.
I don't plan on using them myself but I am curious to know if it really does help or if its an imagined benefit . , over the same period of time you are working and conditioning your horses and they would look better even without the sweats /wraps , ,has anyone ever taken measurements or before and after pics to show the difference ?