According to Gram Research analysis of 15 studies with 434 premature babies, gentle exercise programs may increase bone density by about 0.11 grams per square centimeter and boost weight gain by roughly 3 grams per kilogram of body weight daily during hospitalization. However, the evidence remains low-certainty, and exercise showed little effect on bone length growth or fracture prevention, so larger studies are needed before making firm recommendations.
Premature babies often struggle with weak bones because their bodies didn’t have enough time to develop in the womb. Researchers wanted to know if gentle exercise programs could help these babies build stronger bones and grow better. A Gram Research analysis of 15 studies involving 434 premature babies found that simple movement exercises may help babies gain weight and increase bone density, though the evidence is still limited. The babies in these studies did gentle stretching and range-of-motion exercises for a few weeks while in the hospital. While the results look promising, scientists say we need bigger and better studies to be sure these programs really work.
Key Statistics
A 2026 Cochrane systematic review of 15 randomized controlled trials involving 434 premature babies found that physical activity programs may increase whole-body bone mineral density by 0.11 grams per square centimeter compared to routine care.
According to research reviewed by Gram, premature babies who participated in organized exercise programs gained approximately 2.98 grams per kilogram of body weight per day more than babies without structured physical activity, based on 14 studies with 418 participants.
A 2026 systematic review of 15 trials found very uncertain evidence about whether exercise programs reduce fracture risk in premature infants, with only three studies reporting fracture data and very few fractures occurring in any group.
Research shows that physical activity programs had little to no effect on bone length growth in premature babies, with only a 0.05 centimeter per week difference compared to routine care across 11 studies with 355 participants.
The Quick Take
- What they studied: Whether gentle exercise programs help premature babies develop stronger bones and grow better during their hospital stay
- Who participated: 434 premature babies born before 37 weeks of pregnancy, studied across 15 different research trials. Most studies were small, with between 16 to 50 babies each. The babies were between 26 to 34 weeks old when born.
- Key finding: Babies who did gentle exercise programs gained more weight (about 3 grams per kilogram of body weight per day more) and had slightly denser bones compared to babies who didn’t exercise. However, the exercise didn’t seem to make much difference in how long their bones grew.
- What it means for you: If you have a premature baby in the hospital, gentle movement exercises might help with weight gain and bone strength, but talk to your baby’s doctors about whether this is right for your situation. The evidence is still developing, so this shouldn’t replace standard medical care.
The Research Details
Researchers looked at 15 randomized controlled trials, which are considered the gold standard for medical research. In these trials, some premature babies received organized physical activity programs while others received routine hospital care. The exercise programs involved gentle stretching, bending, and range-of-motion movements done by trained staff. Programs lasted anywhere from three and a half weeks to eight weeks while babies were still hospitalized. Babies started the exercises at different times, ranging from less than three days old to up to four weeks old.
The researchers searched multiple medical databases through October 2025 to find all available studies on this topic. They then combined the results from these studies using a statistical method called meta-analysis, which allows researchers to look at all the data together to see if there’s a clear pattern. They measured bone density using special X-ray machines, tracked how much weight babies gained, measured how much their bones grew, and counted how many babies got fractures.
Premature babies have weak bones because they didn’t spend enough time in the womb developing their skeleton. This condition, called metabolic bone disease, can lead to fractures and other problems. Understanding whether simple exercise can help prevent these problems is important because it’s a safe, non-medication approach that could improve outcomes for thousands of premature babies born each year.
The researchers downgraded the certainty of their findings to low or very low quality for several reasons. Most studies were small, involving only 16 to 50 babies each. The studies had some unclear methods or potential biases in how they were conducted. The results varied quite a bit from study to study, and the confidence intervals were wide, meaning there’s a lot of uncertainty around the exact numbers. These factors mean we should be cautious about how much we trust these results until larger, better-designed studies are completed.
What the Results Show
Physical activity programs appeared to increase whole-body bone mineral density by about 0.11 grams per square centimeter compared to babies who didn’t exercise. This finding came from two studies with 65 babies total and was rated as low-certainty evidence. The researchers found that babies who exercised gained more weight during their hospital stay, about 3 grams per kilogram of body weight per day more than babies without exercise programs. This finding was based on 14 studies with 418 babies and was also rated as low-certainty evidence.
However, the exercise programs had little to no effect on how much babies’ bones grew in length. The difference was only 0.05 centimeters per week, which is too small to matter much. The evidence about whether exercise prevented fractures was very uncertain, with only three studies reporting on this outcome and very few fractures occurring in any group.
The researchers looked for information about other benefits like reduced hospital stays, fewer complications from prematurity, better brain development, and skeletal deformities, but found little usable data. Most studies didn’t measure these outcomes or didn’t report them clearly. This means we don’t know yet whether exercise programs help with these other important aspects of premature baby care.
This is an updated version of a Cochrane systematic review that was first published in 2007 and updated in 2014. The new update added five additional studies, bringing the total to 15. The overall conclusions remain similar to previous versions: exercise may help with bone density and weight gain, but the evidence is still not strong enough to make definitive recommendations. The field hasn’t made major breakthroughs since earlier reviews, suggesting that larger studies are needed.
The biggest limitation is that all included studies were small and conducted at single hospitals, so results might not apply everywhere. Many studies didn’t clearly describe their methods, making it hard to judge their quality. The studies used different exercise protocols and started at different ages, which made it difficult to compare results. Most importantly, no studies followed babies long-term to see if bone benefits lasted after they left the hospital. The researchers had no data on bone mineral content at 12 to 24 months of age, which would show whether benefits persist.
The Bottom Line
Based on low-certainty evidence, gentle physical activity programs may help premature babies gain weight and develop slightly denser bones during hospitalization. However, these programs should only be done under medical supervision by trained staff. Parents should not attempt these exercises at home without professional guidance. Talk with your baby’s medical team about whether a structured exercise program is appropriate for your baby’s specific situation and health status.
Parents of premature babies in the hospital should discuss this with their neonatal care team. Healthcare providers working in neonatal intensive care units may want to consider implementing these programs if they have trained staff available. Researchers studying premature infant health should note that larger, well-designed studies are urgently needed. Babies born at extremely early gestational ages (before 26 weeks) were not included in these studies, so results may not apply to them.
Weight gain benefits appeared within the study periods, which lasted 3.5 to 8 weeks. Bone density improvements were measured at the end of the exercise programs. However, we don’t know how long these benefits last after babies leave the hospital or whether they affect long-term bone health. This is why longer follow-up studies are needed.
Frequently Asked Questions
Do premature babies need special exercise programs to build strong bones?
Premature babies may benefit from gentle, supervised exercise programs during hospitalization. Research shows these programs might increase bone density and weight gain, but evidence is still developing. Always consult your baby’s medical team before starting any program.
How much do exercise programs help premature babies gain weight?
According to research reviewed by Gram, babies in exercise programs gained about 3 grams per kilogram of body weight per day more than babies without structured activity. This modest gain occurred during the hospital stay while exercises were being done.
Can exercise prevent fractures in premature babies?
Current evidence is very uncertain about whether exercise prevents fractures in premature infants. Only three studies measured fractures, and very few occurred in any group. More research is needed to answer this question definitively.
What kind of exercises do premature babies do in these programs?
Programs typically involve gentle stretching, bending movements, and range-of-motion exercises performed by trained hospital staff. Sessions last several weeks during hospitalization. These are passive movements done to the baby, not exercises the baby does independently.
How long do the bone benefits last after premature babies leave the hospital?
We don’t know yet because most studies didn’t follow babies long-term after discharge. This is a major gap in the research, and scientists say larger studies tracking babies for months or years after hospitalization are urgently needed.
Want to Apply This Research?
- If your baby’s medical team recommends an exercise program, track weekly weight gain in grams per kilogram of body weight and note any changes in bone density measurements from hospital scans. Record the dates and types of exercises performed.
- Work with your baby’s healthcare team to ensure prescribed exercises are done consistently during hospitalization. Keep a simple log of exercise sessions completed and any observations about your baby’s response or comfort during activities.
- Request bone density measurements at hospital discharge and ask about follow-up imaging at 12 to 24 months of corrected age. Monitor your child’s growth and development after discharge, and report any concerns about bone health or unusual fractures to your pediatrician.
This article summarizes research findings and should not replace professional medical advice. Premature babies have complex medical needs that require individualized care from qualified healthcare providers. Do not attempt any exercise programs for your premature baby without explicit guidance and supervision from your neonatal care team. The evidence reviewed here is low to very low certainty, meaning results should be interpreted cautiously. Always consult with your baby’s pediatrician or neonatologist before making any changes to your baby’s care plan.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.