Good point. I hadn't thought of it but I used to have bruises on me all the time from hiking and carrying things. Now I don't have any and haven't for quite some time. Hmm.
Supposedly bruising is called by damaged or weak capillaries leaking blood into the surrounding tissues. The weaker the capillary walls, the more likely you are to bruise. Certain blood problems also increase tendency to bruise. Increased tendency to bruise is also considered a normal part of aging.
It would actually make sense that if we improve our overall health, decrease toxin load, decrease N6 intake, etc, which are all known or suspected of improving overall health and cardiovascular health, this could also manifest in lessened tendency towards capillary bleeding.
Increased skin thickness and toughness will also lesson tendency to scratch, bruise or bleed. The greater thickness of the skin gives better protection to the capillaries. It is said that thinning skin is a normal part of aging, but I know that Mark Sisson has talked in the past about him seeming to have better skin thickness than others his age, thus tending to badly throw off the skin pinch test they like to use for determining body fat percentage. Apparently, the same thickness of pinch in an older person compared to a younger person is calculated differently because they assume that older people have thinner skin and therefore they calculate more fat in the older person, even if the same amount of skin is pinched.