Even a minor fall can cause a life-altering fracture for women with osteoporosis. Stronger bones can mean the difference between maintaining independence and facing long-term disability. A recent study found that combining high-intensity interval training (HIIT) with daily vitamin D supplements more than doubled the gains in bone mineral density compared to each intervention alone.

Researchers enrolled 120 sedentary women aged 30 to 50, all diagnosed with osteoporosis. They randomly assigned participants to one of four groups: a control group, a vitamin D group (800 IU per day), an exercise-only group (16 weeks of HIIT), and a combined group that did both. Before and after the intervention, researchers measured bone mineral density of the hips and spine and markers of bone turnover in the blood.

They found that the group combining HIIT and vitamin D supplementation showed the greatest improvements in bone mineral density at the hips and lumbar spine, with a 3.2% improvement in hip bone mineral density, surpassing the 1.5% increase in the HIIT-only group and the 1.2% increase in the vitamin D-only group. Blood levels of calcium and osteocalcin increased the most in the combined group, while bone-specific alkaline phosphatase (a marker of bone breakdown) decreased. Improvements in bone mineral density were linked to higher calcium and osteocalcin levels and lower body mass index.

These findings suggest that pairing HIIT with vitamin D supplements boosts bone strength in women with osteoporosis, helping to slow or even reverse bone loss during midlife. Learn more about the effects of HIIT on bone density in this clip featuring Dr. Martin Gibala.