I have this problem - and I'm sure many people do too - it made for a good excuse not to walk
One is thighs rubbing together - the other is the perspiration of exercise making for a soggy walk...
But I discovered two solutions to making sure that those issues were resolved and now I'm an avid hiker, doing 3-6 miles each time out.
1) Get yourself a stick of Glide (I think thats what its called) from a runner's store or web site. Its like a stick deodorant - runners use it to eliminate chaffing in their shoes and seams of clothing and other places. Apply it between those thighs and you you'll never rub again!
2) This is going to sound gross but is probably not uncommon to overweight women. Sweat. Between the legs. Nothing worse than to feel like you're wearing a wet diaper when you're exercising - particularly in the summer months. So - my solution? I bought a half dozen pairs of wicking material, boxer style underwear from a sporting goods web site. They look like mens briefs - but they're made from Duofold material. I wish they were longer - they roll sometimes - but even rolled, they catch moisture and wick it away - so I'm never soggy and miserable when I walk.
You might also consider wearing the longer, thigh length biker shorts under regular shorts too - as long as its intended to be for exercise and has a wicking material, you'll get the same benefits. I've purchased a bunch of duofold tanks too, with the same material and its amazing what a difference it makes!
Hope this helps someone get out there
Eliminating excuses - some walking ideas
