N/A N=18 Other

Enhancing Skeletal Adaptations to PTH and Exercise

Exercise · Bone Resorption · Bone Formation

Bottom Line

View on ClinicalTrials.gov: NCT05029128 ↗

Enrolled (actual)

Serious AEs

0.0%

Results posted

Apr 2026

Primary outcome: Primary: Change in C-terminal Peptide of Type 1 Collagen (CTX) — 0.03; 0.03; 0.05; 0.03 ng/mL

Study Design & Population

Study type: Interventional
Phase: N/A
Interventions: Endurance exercise intervention (Behavioral)
Age: Adult, Older Adult · 25+ yrs
Sex: All
Sponsor: VA Office of Research and Development
Primary completion: Apr 2025

Outcome Measures

Outcome	Result	p-value
PRIMARY Change in C-terminal Peptide of Type 1 Collagen (CTX)	0.03; 0.03; 0.05; 0.03	—
PRIMARY Change in Procollagen 1 Intact N-terminal Propeptide (P1NP)	-7.5	—
SECONDARY Change in P1NP During Exercise	0.0; 9.3; 7.2; 5.4	—
SECONDARY Urinary Calcium Excretion (uCa)	37.9; 21.5; 22.5; 27.5	—
SECONDARY Change in Serum Ionized Ca (iCa)	-0.21; -0.22; -0.18; -0.20	—
SECONDARY Change in Serum Total Ca (tCa)	0.01; 0.10; -0.02; 0.03	—
SECONDARY Change in Serum Parathyroid Hormone (PTH)	15.4; 16.1; 14.0; 15.2	—
SECONDARY Change in Serum Phosphorus (PO4)	0.19; 0.23; 0.10; 0.18	—
SECONDARY Change in Hematocrit (Hct)	-0.38; 0.57; -0.33; -0.05	—
SECONDARY Change in Hemoglobin (Hgb)	-0.18; 0.23; 0.15; 0.05	—

Summary

Exercise is essential for building and maintaining bone mass and strength, but current exercise recommendations for how to achieve this lack detail on the optimal exercise prescription. Recent studies found that blood calcium level decreases during exercise, and that calcium is mobilized from bone to slow the decline. If this occurs repeatedly during exercise training, it could diminish the potential benefits of exercise to improve bone health. The proposed study will determine whether further research on pre-exercise supplemental calcium to minimize the decline in blood calcium level during exercise is warranted. This research is important for Veterans because they are at increased risk of hip fracture when compared with non-Veterans. Further, because osteoporosis in men is under-recognized and under-treated, providing male (and female) Veterans with more specific exercise and nutrition guidelines has the potential to enhance bone health, reduce fracture risk, and improve quality of life.

Eligibility Criteria

Inclusion Criteria

Female and male Veterans aged 25 to 45 y and 55 to 75 y will be enrolled. Eligible volunteers will be normally active (e.g., recreational cycling or walking) but will not participate in regular moderate-to-vigorous exercise. Women will be premenopausal with regular menstrual cycles or postmenopausal, defined as absence of menses for at least 12 mo or, in those who underwent a hysterectomy, a serum follicle stimulating hormone (FSH) >30 mIU/mL.

Exclusion Criteria

Initiation or change in dose in the past 6 months of medications that affect bone metabolism
e.g., osteoporosis medications, thiazide/loop diuretics, systemic glucocorticoids
BMD T-score 5.0 mU/L
Serum Ca 10.3 mg/dL
Serum 25(OH)D 150 mmHg or diastolic BP >90 mmHg)
Type 1 diabetes
Type 2 diabetes if on insulin or sulfonylurea therapy
hemoglobin A1c >7%
Cardiovascular disease; defined as subjective or objective indicators of ischemic heart disease (e.g., angina, ST segment depression) or serious arrhythmias at rest or during the graded exercise test (GXT)
volunteers who have a positive GXT can be re-considered after follow-up evaluation by a cardiologist
Anemia (hemoglobin 39 kg/m2
In the event of abnormal eGFR, alkaline phosphatase, TSH, BP, 25(OH)D, or hemoglobin values, volunteers can be reassessed, including after appropriate follow-up evaluation and treatment by their health care provider

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT05029128). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.