My wife and I love to go hiking. In fact, we spent our honeymoon in Zion National Park, Bryce Canyon National Park, and the North and South Rims of the Grand Canyon. But before we ever set foot on a trail, we went out and purchased the most important piece of equipment necessary for weeks of non-stop, hiking; hiking boots.
Even though we would be hiking the same trails, under the same conditions, the basic differences between male and female feet meant we would not be getting the same boots. So what are the differences in our feet that make the construction of mens hiking boots and womens hiking boots so different.
Most obviously, women's feet are shorter and narrower than men's feet. This in itself is expected, since (in general) women are shorter and lighter than men. However, part of this is due to the fact that there is less cartilage between the bones of a woman's foot and her joints and ligaments are softer and more flexible. Also, a woman's heel is proportionally narrower than a man's. Boot manufacturers now compensate for this by either molding a tighter heel box, or adding additional stiff padding to hold the heel snugly in place to reduce sliding.
The effect of the increased flexibility of a woman's foot resulted in two design improvements in the women's boot. First, the more flexible woman's foot requires more support to withstand the continuous stress of hiking. This is generally accomplished by the addition of stiffer mid sole support, such as an insert. The insert is usually molded into the sole in order to retain the traction required for all types of terrain, yet remain flexible enough for a comfortable stride. The second, and possibly more important difference in the mid sole is the enhanced arch support in the woman's boot.
In general, a woman has a higher arch than a man, which needs additional support. However, due to the monthly changes in a woman's hormone levels, specifically estrogen, the arch of her foot actually decreases, since estrogen is a soft tissue relaxant. This relaxation of an already flexible foot causes the shape of a woman's foot to cycle between a relatively high arch and a flat foot. This fluctuation in the arch makes it critical for the mid sole of a woman's boot to have an enhanced (stiffer) arch support.
One manufacturer (Lowa) has taken the difference in foot structure a step further, since it also creates a difference in posture. A man's stance and stride is not as upright as a woman's so Lowa has designed a 2 degree offset into the ankle shaft of their mens hiking boots in order to provide a more balanced stance. Since women have a naturally more upright stance, this offset does not exist in the ankle design of their womens hiking boots.
Understanding the differences between mens hiking boots and womens hiking boots should make it much easier for you to select a proper fitting boot. Just because a womans foot is naturally smaller, do not assume that purchasing a smaller sized mans boot is the way to go. The best option is to try on hiking boots that are specifically designated as women's hiking boots. This immediately tells you that the manufacturer understands the differences between a man's foot and a woman's foot, and has designed their boots to address those differences.