Study analysis · Journal of Sports Sciences · 2024
6 months of exercise won't boost your 'anti-aging' protein or vitamin D — but here's what actually dropped.
Exercising for 6 months at any intensity doesn't change S-Klotho or vitamin D levels in young adults, and vitamin D naturally falls in winter regardless of exercise.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
Imagine you want to know if exercise changes certain chemicals in your blood. This study took 144 young adults and randomly split them into groups: some did hard exercise, some did medium exercise, and some did no exercise. After 24 weeks, they measured the chemicals and found that exercise didn't make any difference. So we can be quite sure that for young adults, these particular chemicals aren't changed by this kind of exercise.
What’s the bottom line?
Scientists asked if 6 months of exercise at different intensities could increase S-Klotho (a protein linked to aging) or vitamin D levels in healthy young people.
How strong is this study?
The study was like a fair coin toss to decide who exercised and who didn't, which is good. But everyone knew which group they were in, so people might have acted differently. Also, the blood tests were done carefully, so the results are trustworthy. Overall, it's a decent study, but because it was done in one place with one age group, we can't be sure it applies to everyone.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
69 / 100
- Randomization+20/20
- Blindingnot blinded
- Control group+15/15
- Sample size (n=144)+10.3/20
- Follow-up+10/10
100 / 100
46 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 556 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Unblinded design may introduce performance bias, but objective lab outcomes reduce detection bias. Results are null, so causal inference of 'no effect' is supported.
No Conflicts
No conflicts of interest identified
No conflicts of interest identified from the available metadata; funding is from public research agencies.
Funders
Only repository metadata was provided; full text may contain additional COI details.
Key takeaways
- 01
Exercise did not change S-Klotho or vitamin D levels.
- 02
Vitamin D levels dropped in all groups over time, likely because of winter.
- 03
For a healthy young person, adding regular exercise for 6 months probably won't raise their S-Klotho or vitamin D levels.
Surprising findings
- Vitamin D decreased over time in all groups, including exercisers, with a significant time effect (p<0.001).We often assume physical activity outdoors boosts vitamin D, but this study was indoors. It highlights that without sun exposure, exercise alone doesn't raise vitamin D.
- S-Klotho remained unchanged even after 24 weeks of supervised exercise (p=0.497 for time effect).Prior research in older adults showed exercise increases S-Klotho. This study contradicts the idea that it works the same way in young people.
Practical takeaways
If you're a healthy young adult, don't rely on indoor exercise to boost vitamin D — get 10-15 minutes of midday sun or consider supplementation in winter.
This study didn't test outdoor exercise or supplementation; also, null results don't mean exercise is useless for other health markers.
low confidenceDon't expect gym workouts to increase your S-Klotho levels as a young adult — focus on other benefits like cardiovascular fitness and strength.
The study is a secondary analysis with moderate confidence; other biomarkers might respond differently.
low confidenceWhy this study matters
The null result that should make you skeptical
After 24 weeks of supervised exercise (moderate or vigorous intensity), S-Klotho and 25-hydroxyvitamin D levels showed no significant change compared to controls. Time-by-group interaction p-values were both >0.7, meaning exercise had virtually zero effect.
It challenges the common narrative that exercise boosts 'anti-aging' proteins and vitamin D — at least for healthy young people.
Vitamin D dropped in EVERYONE — even the exercisers
25-hydroxyvitamin D decreased significantly over time across all groups (p<0.001), regardless of exercise. The study notes this is likely due to seasonal changes (winter) reducing sun exposure.
It shows that indoor exercise can't compensate for lack of sunlight in winter, which is a practical takeaway for vitamin D levels.
S-Klotho stability: Is it a young adult thing?
S-Klotho plasma levels did not change over time in any group (p=0.497). The authors suggest that in healthy young adults, this 'anti-aging' protein may already be at optimal levels and exercise doesn't upregulate it further.
This contrasts with studies in older or diseased populations where exercise increases S-Klotho. Age matters!
Intensity doesn't matter — both groups got null results
The study compared vigorous-intensity exercise (close to HIIT) vs. moderate-intensity (brisk walking/jogging). Neither changed S-Klotho or vitamin D. The conclusion: intensity isn't the issue — exercise simply doesn't affect these markers in young adults.
Many fitness influencers claim high-intensity is superior for health biomarkers. This study says: not for these ones.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists asked if 6 months of exercise at different intensities could increase S-Klotho (a protein linked to aging) or vitamin D levels in healthy young people.
Research results
Exercise did not change S-Klotho or vitamin D levels. Vitamin D levels dropped in all groups over time, likely because of winter.
What this means - more context
For a healthy young person, adding regular exercise for 6 months probably won't raise their S-Klotho or vitamin D levels.
To investigate the effects of 24-week supervised concurrent exercise training at moderate or vigorous intensity on S-Klotho and 25-hydroxyvitamin D plasma levels in young adults.
A randomized controlled trial with 144 young adults assigned to vigorous exercise, moderate exercise, or control. No significant changes in S-Klotho or vitamin D were observed due to exercise; vitamin D decreased over time in all groups due to seasonal factors.
Methods Used
Secondary analysis of the ACTIBATE single-center unblinded RCT. 144 participants (18-25 years) randomized to vigorous concurrent exercise, moderate concurrent exercise, or control. Plasma S-Klotho and 25-hydroxyvitamin D measured before and after 24 weeks.
Main Finding
Twenty-four weeks of supervised concurrent exercise, regardless of intensity, does not significantly alter S-Klotho or 25-hydroxyvitamin D plasma levels in young adults (time × group interaction p > 0.7 for both).
Confidence Level
Moderate – well-designed RCT but secondary analysis, unblinded, and null results with no effect sizes reported.
Study Flags
Red Flags
- •Secondary analysis of a trial not originally designed for these outcomes
- •Unblinded design
- •No reported effect sizes or confidence intervals
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Vitamin D decreased over time in all groups, including exercisers, with a significant time effect (p<0.001).
We often assume physical activity outdoors boosts vitamin D, but this study was indoors. It highlights that without sun exposure, exercise alone doesn't raise vitamin D.
Practical Takeaways
If you're a healthy young adult, don't rely on indoor exercise to boost vitamin D — get 10-15 minutes of midday sun or consider supplementation in winter.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 556 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
Imagine you want to know if exercise changes certain chemicals in your blood. This study took 144 young adults and randomly split them into groups: some did hard exercise, some did medium exercise, and some did no exercise. After 24 weeks, they measured the chemicals and found that exercise didn't make any difference. So we can be quite sure that for young adults, these particular chemicals aren't changed by this kind of exercise.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized allocation
- Inclusion of a control group (no exercise)
- Supervised exercise training for 24 weeks
Weaknesses
- Unblinded (participants and staff knew group assignments)
- Secondary analysis of a trial not originally designed for these outcomes
- Single-center design
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists asked if 6 months of exercise at different intensities could increase S-Klotho (a protein linked to aging) or vitamin D levels in healthy young people.
Research results
Exercise did not change S-Klotho or vitamin D levels. Vitamin D levels dropped in all groups over time, likely because of winter.
What this means - more context
For a healthy young person, adding regular exercise for 6 months probably won't raise their S-Klotho or vitamin D levels.
To investigate the effects of 24-week supervised concurrent exercise training at moderate or vigorous intensity on S-Klotho and 25-hydroxyvitamin D plasma levels in young adults.
A randomized controlled trial with 144 young adults assigned to vigorous exercise, moderate exercise, or control. No significant changes in S-Klotho or vitamin D were observed due to exercise; vitamin D decreased over time in all groups due to seasonal factors.
Methods Used
Secondary analysis of the ACTIBATE single-center unblinded RCT. 144 participants (18-25 years) randomized to vigorous concurrent exercise, moderate concurrent exercise, or control. Plasma S-Klotho and 25-hydroxyvitamin D measured before and after 24 weeks.
Main Finding
Twenty-four weeks of supervised concurrent exercise, regardless of intensity, does not significantly alter S-Klotho or 25-hydroxyvitamin D plasma levels in young adults (time × group interaction p > 0.7 for both).
Confidence Level
Moderate – well-designed RCT but secondary analysis, unblinded, and null results with no effect sizes reported.
Study Flags
Red Flags
- •Secondary analysis of a trial not originally designed for these outcomes
- •Unblinded design
- •No reported effect sizes or confidence intervals
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Vitamin D decreased over time in all groups, including exercisers, with a significant time effect (p<0.001).
We often assume physical activity outdoors boosts vitamin D, but this study was indoors. It highlights that without sun exposure, exercise alone doesn't raise vitamin D.
Practical Takeaways
If you're a healthy young adult, don't rely on indoor exercise to boost vitamin D — get 10-15 minutes of midday sun or consider supplementation in winter.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 556 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
Imagine you want to know if exercise changes certain chemicals in your blood. This study took 144 young adults and randomly split them into groups: some did hard exercise, some did medium exercise, and some did no exercise. After 24 weeks, they measured the chemicals and found that exercise didn't make any difference. So we can be quite sure that for young adults, these particular chemicals aren't changed by this kind of exercise.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized allocation
- Inclusion of a control group (no exercise)
- Supervised exercise training for 24 weeks
Weaknesses
- Unblinded (participants and staff knew group assignments)
- Secondary analysis of a trial not originally designed for these outcomes
- Single-center design
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study was like a fair coin toss to decide who exercised and who didn't, which is good. But everyone knew which group they were in, so people might have acted differently. Also, the blood tests were done carefully, so the results are trustworthy. Overall, it's a decent study, but because it was done in one place with one age group, we can't be sure it applies to everyone.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
69 / 100
- Randomization+20/20
- Blindingnot blinded
- Control group+15/15
- Sample size (n=144)+10.3/20
- Follow-up+10/10
100 / 100
46 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 556 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Unblinded design may introduce performance bias, but objective lab outcomes reduce detection bias. Results are null, so causal inference of 'no effect' is supported.
No Conflicts
No conflicts of interest identified
No conflicts of interest identified from the available metadata; funding is from public research agencies.
Funders
Only repository metadata was provided; full text may contain additional COI details.