A team of researchers from Johns Hopkins University School of Medicine conducted a study to determine how vitamin D “sunshine vitamin” and exercise work together versus being on their own. The findings revealed that the two factors appear to work together better for protecting the cardiovascular system than either on their own.
When combining the two health factors together there is a reduction in the risk of events such as strokes and heart attacks. The findings also demonstrate that exercise may contribute in increasing vitamin D levels in the blood.
The researchers examined health records and surveys of an estimated 10,000 American adults for over a 20-year period. While both exercise and vitamin D have been known to decrease the risks of heart disease, this study primarily focused on the direct relationship between exercise and vitamin D, along with their mutual role in heart health.
In the study, it was common for people to fail to meet their recommended physical activity levels and have a vitamin D deficiency. Exercise levels directly and positively correlated with vitamin D levels, which basically means that the more one exercises, the higher their vitamin D levels. The participants who met their recommended exercise levels decreased their risks of vitamin D deficiency by 31 percent.
However, this positive relationship was only present in the white participants and not African-Americans.
During the second phase of the study, the researchers discovered that participants, who were the most active and had the highest vitamin D levels, also had the lowest risk for developing cardiovascular disease later on in life. Particularly, all participants in that group experienced nearly 23 percent less probability of an adverse cardiac event like a stroke, heart attack or death related to heart disease or even a stroke.
Participants with vitamin D deficiency but had adequate exercise did not have decreased risk of adverse events. That is to say that the combined benefits of exercise and vitamin D were much stronger than either health factor alone.
According to the researchers, sun exposure may very well not be the entire story in the connection between exercise and vitamin D, since the vitamin D levels did not gradually decrease for the participants as they normally do, when the body produces sufficient vitamin D through sunlight. This discovery indicates that other factors may also play a role in causing exercise and vitamin D to impact each other – in all likelihood, healthier habits and lifestyles for individuals who exercise.
The racial disparity discovered in this study could imply that increased physical activity may not be as helpful for boosting vitamin D levels in African-Americans as in whites. The researchers note that people with relatively dark skin produce vitamin D less efficiently after sun exposure, which is probably related to higher amounts of melanin.
The researchers caution taking more than the recommended daily amount of vitamin D, which is between 600 to 800 International Units, could increase risks of vitamin D toxicity. A healthy lifestyle and diet, along with adequate sun exposure is the best way to ensure adequate vitamin D levels.
The researchers note that it has not yet been proven that vitamin D supplements are beneficial to heart health and recent studies have failed to reveal any genuine cardiovascular benefits with higher monthly doses of vitamin D supplements.
The study was published in The Journal of Clinical Endocrinology & Metabolism (JCEM) on February 17, 2017.