A new study shows a strong connection between vitamin D supplementation and cardiorespiratory fitness. Also known as the “sunshine” vitamin (since it is not easily obtained from food sources and sunlight is the best source), vitamin D helps the body absorb calcium and phosphorus to build bones, and can protect older adults from osteoporosis. Vitamin D also supports the immune system and may reduce the risk of some cancers.
The study, published in the European Journal of Preventive Cardiology, used data from the National Health and Nutrition Survey (2001 to 2004) on adults between 20 and 49 to determine the relationship between vitamin D levels in the blood and VO2 max, a measure of how much oxygen your body can deliver to your muscles during hard exertion (commonly used to assess fitness). They threw out the data on subjects in the top or bottom five per cent for vitamin D levels, which might skew the results.
The investigation showed that “participants in the highest quartile of vitamin D levels had a significantly higher CRF [cardiorespiratory fitness] than participants in the lowest quartile.” Each 10 nmol/L (nanomole per litre) increase in vitamin D was associated with a significant increase in VO2 max, leading researchers to conclude that there is a strong relationship between vitamin D levels and fitness. However, clinical trials are needed to establish whether there is a direct causal link between supplementation and increased fitness potential.
Many Canadians are vitamin D deficient and take supplements, due mainly to our long winters. It’s useful to know that supplementation to boost vitamin D levels may have potential fitness benefits, as well as benefiting your overall health.