|Centers for Disease Control and Prevention|
Researchers from Johns Hopkins Medicine found "a positive and direct relationship" between exercise and vitamin D levels, "which may provide evidence that exercise may boost vitamin D stores" and "that the two factors working together seemed to somehow do more than either factor alone to protect the cardiovascular system."
This research provides yet one more reason why Kentucky adults, one-third of whom say they aren't physically active, need to get up and start moving -- especially in a state that leads the nation in heart disease.
The study, published in The Journal of Clinical Endocrinology & Metabolism, analyzed survey responses and health records of more than 10,000 adults over nearly 20 years. The researchers point out that the study wasn't designed to show cause and effect, but to simply look at the relationship between these two health factors and their role in heart health.
The analysis looked at self-reported exercise levels and compared them to the American Heart Association's recommendations of more than 150 minutes per week of moderate intensity exercise or 75 minutes per week of vigorous intensity. Using these criteria, researchers placed participants into three categories: adequate (those who met the AHA recommendations), intermediate (those who exercised, but less than the AHA recommendations) or poor (those who didn't exercise at all).
The study found that about 60 percent of the participants had inadequate exercise and were in the poor or intermediate categories and 30 percent had inadequate vitamin D levels.
“In our study, both failure to meet the recommended physical activity levels and having vitamin D deficiency were very common,” Dr. Erin Michos, one of the researchers in the study, said in the news release. “The bottom line is we need to encourage people to move more in the name of heart health.” She also encouraged daily exposure to sunlight and eating a well-balanced diet that includes oily fish such as salmon, along with fortified foods like cereal and milk to improve vitamin D levels.
The study found that the more the participants exercised, the higher their vitamin D levels were, except among African Americans. Michos said she didn't know why, but noted that people with darker skin produce vitamin D less efficiently after sun exposure, possibly because they have more skin pigment. African Americans also tend to have lower vitamin D levels overall, but don't seem to have the same risks, such as bone fractures, as whites with similarly low levels.
The study also found that the most active participants with the highest vitamin D levels had the lowest risk for future cardiovascular disease. After adjusting for other risk factors, the researchers found that those who were most active with the highest vitamin D levels were about 23 percent less likely of having "an adverse cardiovascular event" than those with poor physical activity and deficient vitamin D levels.
"The combined benefit of having adequate vitamin D and exercise levels was better than either health factor alone," said the release.
Michos cautioned that people who get the recommended daily amount of Vitamin D, 600 to 800 International units, don’t need to take additional vitamin supplements. She said the benefits of vitamin D supplements haven't yet been proven to benefit heart health, though researchers continue to study this.
“People [who are] at risk of bone diseases, have seasonal depression, or are obese should have their physicians measure vitamin D levels to ensure they’re adequate, but for many, the best way to ensure adequate blood levels of the vitamin is from sun exposure, healthy diet, being active and maintaining a normal body weight," she said.