Want to get fit? Check your vitamin D levels. Cardiorespiratory fitness (CRF) may well be linked to serum vitamin D levels. A study, published in the European Journal of Preventive Cardiology (October 30, 2018), looked at data from nearly 2,000 participants in the National Health and Nutrition Survey. Subjects were between the ages of 20 and 49.
Researchers used VO2 max as an indicator of cardiorespiratory fitness. Used to establish the aerobic endurance of an athlete, VO2 max is the amount of oxygen a person can utilize during intense exercise. By putting a face mask on the subject, the volume and gas concentrations of inspired and expired air can be directly measured.
Of the 1995 participants, 45.2% were women, 49.1% were white, 13% were hypertensive and 4% had diabetes. Vitamin D levels did not vary between matched subjects with confounding variables like diabetes, high blood pressure, age, sex, race, CRP levels, BMI, etc. The one variable that did make a difference between matched subjects was serum vitamin D levels. The researchers found that serum vitamin D levels had a significant effect on cardiorespiratory fitness (VO2 max). Those in the highest quadrille had a VO2 max 2.9 higher on average than those in the lowest quadrille.
According to the authors, “We found a strong independent association between vitamin D levels and CRF, which was robust to potential confounding variables. Future studies are needed to explore the underlying biological mechanisms of the observed association. Clinical trials of vitamin D supplementation are required to validate the relationship.”
Vitamin D levels have been associated with other cardiovascular issues. Low levels are linked to a higher risk of hypertension, poor outcomes for congestive heart failure patients and overall cardiac mortality. Now we can add cardiorespiratory fitness to that list. Because CRP status may be an indicator of cardiovascular risk, the American Heart Association has recommended that CRP be measured in routine clinical practice.