Bone Density
Table of contents
The same DEXA scan that measures fat and muscle also measures how dense my bones are. This is the quiet good-news story of the series: my bones were already in good shape in April, and October didn’t change that. October’s number also looks like a big jump, but I’m not reading much into it, and the scan report itself says why.
Snapshot
| April 2026 | October 2026 | Status | |
|---|---|---|---|
| Whole-body BMD | 1.216 g/cm² | 1.275 g/cm² | ✅ |
| Whole-body T-score | 0.2 | 0.8 | ✅ |
| Whole-body Z-score | 0.1 | 0.7 | ✅ |
| Lumbar spine (L1–L4) Z-score | +1.5 | not scanned | ✅ |
| Hip (femoral neck) Z-score | −0.2 | not scanned | ✅ |
What it is
BMD (bone mineral density) is how much mineral is packed into a given area of bone. More is better. Low BMD means weaker bones and a higher risk of fractures.
The scan reports two comparison scores:
- T-score compares you to a healthy young adult at peak bone mass. This is the one used to diagnose osteoporosis, mainly after menopause or in men over 50. −1 and above is normal.
- Z-score compares you to people of your own age and sex. This is the one that matters for someone my age. A Z-score of −2.0 or lower is “below the expected range for age” and worth investigating. Anything above that is fine.
What I’m aiming for
- Z-scores comfortably above −2.0 at every site, ideally above 0.
- No drop over time. Peak bone mass is reached around your late 20s to 30s, so the job now is to hold onto it.
Was April a problem?
No. April was the full bone scan (spine, hip and whole body), and the radiologist’s report said all my Z-scores were within the expected range, the WHO classification was normal, and fracture risk wasn’t increased. My spine was above average for my age (Z-score +1.5). The hip was close to average (−0.2), which is still well within normal.
October: higher, but don’t over-read it
October’s scan was whole-body only (no separate spine or hip scans), and the whole-body BMD came back 0.059 g/cm² higher, a 4.9% increase. On paper that’s a big jump, well above the 0.014 g/cm² the scan counts as a real change.
But look at the # next to the change in the report snippet above. It means “dissimilar scan types or analysis methods”. The two scans weren’t set up the same way, so the machine itself is saying it can’t fairly compare them. Bone also changes slowly, and a real 5% gain in six months would be unusual for an adult.
What I take from it: my bones are still normal to good, and nothing went backwards during a big cut, which is the main thing I’d want to know.
What probably helps my bones generally:
- Load. BJJ and strength training put force through the bones, which is the main signal for them to stay dense.
- Vitamin D, which went from insufficient to desirable over the same period (see Vitamin D).
- Enough protein and calcium. My blood calcium was normal both times.
What’s next
- No action needed. Keep lifting and grappling once my injuries allow.
- Being very lean for a long time can be hard on bones, which is another reason not to chase lower body fat (see Body Fat).
- If I scan again, I’ll ask for the same scan type as last time so the numbers are comparable.
This is my own personal data, shared for interest only. It’s not medical advice.
Until next time, peace and love!