I did get my blood work back and it was all excellent. Iron and calcium levels were very good. Vit D was in the normal range but on the lower side (40.3 where normal range is 30-100). Besides upping my Vit D and continuing with calcium/magnesium supplents, and adding more lower body strength work, any other suggestions?
Ask for an NTX study. Chances are it will come back normal, but it’s worth a try. It’s a urine sample and they check Ca excretion.
Has anyone else had experience reversing low bone density and doing triathlons/marathons?
Yup. I suffered from anorexia from 2000-2005. I was diagnosed with osteoporosis in my spine and osteopoenia in my hips in early 2005 (I was 18). Fairly common “side effect” of anorexia. After a couple of years of being at the low end of a healthy weight I went to low normal hips, spine on the border of osteopoenia/osteoporosis. It has been about 6 years since my last DEXA scan so I can’t tell you what they are now.
I had a rash of stress fractures from 2005 - 2009 and another in 2012 (fibula, metatarsals on two or three separate occasions, also possibly one in my hip - I had hip tendonitis and it was hard to tell from the images whether there was a fracture or not, but given the pain I suspect it was at the very least a stress reaction). While the low bone density probably contributed to it, I think the main problem was that I just tried to run too many miles. For a good stretch of my anorexia I ran about 13 miles a day every day, and never had any injuries or bone issues. It was very puzzling to go from that, to running 50 mpw - about half of what I’d done - and get so hurt. The explanation from someone smarter than myself was that my bones needed some time to adjust to the 20 pounds I had to gain. I’ve been running 50 miles a week for the past several years with no issues. Also, while I should lift, I don’t … it’s not like I can point to a bunch of exercises with weights I’ve been doing for years that “magically” changed things for me.
I think that one reason I am able to run so much is that with the exception of racing and the very occasional run on a track, I do all of my miles on a treadmill. You can substitute some other soft surface here if you want to be outside - a grass field, or trail, or whatever - but pavement is hard stuff, and when I got fractures, I was running on pavement most of the time. I would rather run 50 mpw on the treadmill than 30 miles outside, I guess.
In addition to the lower body strength conditioning you mentioned, I’d do upper body stuff and stuff to strengthen your lower back and shoulders… hips and spine. I think they do hip and spine because they’re likely spots to fracture, or because you can end up with that dowager’s hump, but I was also told that if hip and spine are low, other bones likely are as well - so from a long term health perspective it’s good to strengthen everything.