Indoor athletes have 4.5 ng less Vitamin D (Asia in this case) – meta-analysis April 2023

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Difference in Levels of Vitamin D between Indoor and Outdoor Athletes: A Systematic Review and Meta-Analysis

Int J Mol Sci . 2023 Apr 20;24(8):7584. doi: 10.3390/ijms24087584 DOI: 10.3390/ijms24087584
Maria Bârsan 1, Vlad-Florin Chelaru 2, Armand-Gabriel Râjnoveanu 1, Ștefan Lucian Popa 3, Andreea-Iulia Socaciu 1, Andrei-Vlad Bădulescu 2

Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus far. Variances in exposure to sunlight can cause vitamin D levels to fluctuate. Indoor activity can be a factor for these fluctuations and can lead to a decrease in vitamin D levels. We conducted a systematic review and meta-analysis aiming to identify whether indoor compared to outdoor training has a significant influence on vitamin D levels; we also performed subgroup analyses and multivariate meta-regression. The type of training has an impact on vitamin D levels that is influenced by multiple cofounders. In a subgroup analysis not considering cofounders, the mean serum vitamin D was 3.73 ng/mL higher in outdoor athletes, a difference which barely fails to achieve significance (p = 0.052, a total sample size of 5150).
The indoor-outdoor difference is only significant (clinically and statistically) when considering studies performed exclusively on Asian athletes (a mean difference of 9.85 ng/ml, p < 0.01, and a total sample size of 303). When performing the analyses within each season, no significant differences are observed between indoor and outdoor athletes.
To control for multiple cofounders (the season, latitude, and Asian/Caucasian race) simultaneously, we constructed a multivariate meta-regression model, which estimated a serum vitamin D concentration lower by 4.446 ng/mL in indoor athletes. While a multivariate model suggests that outdoor training is associated with slightly higher vitamin D concentrations when controlling for the season, latitude, and Asian/Caucasian race, the type of training has a numerically and clinically small impact. This suggests that vitamin D levels and the need for supplementation should not be decided based on training type alone.
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VitaminDWiki – Overview Sports and vitamin D contains

Athletes are helped by vitamin D by:

1. Faster reaction time
2. Far fewer colds/flus during the winter
3. Less sore/tired after a workout
4. Fewer micro-cracks and broken bones
5. Bones which do break heal much more quickly
6. Increased VO2 and exercise endurance Feb 2011
7. Indoor athletes especially need vitamin D
8. Professional indoor athletes are starting to take vitamin D and/or use UV beds
9. Olympic athletes have used UV/vitamin D since the 1930's
10. The biggest gain from the use of vitamin D is by those who exercise less than 2 hours per day.
11. Reduced muscle fatigue with 10,000 IU vitamin D daily
12. Muscle strength improved when vitamin D added: 3 Meta-analysis
13. Reduced Concussions
    See also: Sports and Vitamin D category 282 items

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VitaminDWiki – Sports categrory contains

282 items in Sports category

Sports benefits from up to 50 ng (click on chart for details)

see also:
Overview Sports and vitamin D     Concussions
Military    Muscle    Overview Fractures and vitamin D
Vitamin D supplementation increases strength of lower muscles – Meta-analysis April 2019
Athletes helped by weekly 50,000 IU Vitamin D – RCT Aug 2019
College swimmers helped by daily 5,000 IU of Vitamin D in the fall – RCT Feb 2020
Shin splints decrease with vitamin D
Less muscle inflammation after exercise if high level of Vitamin D (50 ng) -July 2021 50 ng
Only 1 NCAA basketball player getting 10,000 IU vitamin D daily achieved 50 ng goal – Jan 2020 50 ng
NCAA trainers are getting on board the Vitamin D train (40-50 ng)– Nov 2019 50 ng
Is 50 ng of vitamin D too high, just right, or not enough 50 ng
The only independent predictor of aerobic power: Vitamin D - 2021
Olympic Committee consensus on Vitamin D, Omega-3, Zinc, etc– May 2018 not consdered "doping"
Some Foot and ankle problems are treated by Vitamin D – many studies
Typical stress fracture during US Navy training cost 14,953 dollars, most had less than 40 ng Vitamin D - June 2022
Vitamin D trials by military – all 4 found benefit – review Sept 2019
Vitamin D supplementation increases strength of lower muscles – Meta-analysis April 2019
Omega-3 helps muscles - many studies

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VitaminDWiki – Shut-in category has 39 items along with related searches

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VitaminDWiki – Shiftwork. like indoor sports, also reduces Vitamin D

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