Contrary to what most people believe, vitamin D is not a vitamin but a steroid hormone. It is produced in various parts of the body but exerts its influence elsewhere in the body—which is what hormones do. Your body can manufacture vitamin D on its own when your skin is exposed to sunlight. Just 15 minutes a day with your legs and face exposed to the sun without sunscreen several days a week usually supplies sufficient amounts of vitamin D. If you can’t get out in the sun, live in northern climates where there is not too much sunlight, or frequently wear sunscreen, you may need to take supplements. The form of vitamin D manufactured by the liver and measured in the bloodstream is called calcidiol, or 25 hydroxyvitamin D-2. The activated vitamin D steroid hormone is processed by the kidneys and is known as calcitriol, or 25 hydroxyvitamin D-3. Calcitriol circulates as a hormone in your body regulating the amounts of calcium and phosphate in your bloodstream and maintaining the health of your bones.
As a steroid hormone, vitamin D regulates more than 1,000 vitamin D–responsive human genes and may influence athletic performance, particularly if you are deficient in this nutrient. Numerous studies over many decades have revealed that physical and athletic performance peaks when 25 hydroxyvitamin D-2 levels peak in the summertime and declines as the steroid hormone declines in the body in the wintertime. Athletes tend to have low vitamin D levels in winter, according to a number of studies. Several studies also document low vitamin D levels in athletes that participate in indoor sports. If you’re an older athlete, make sure you get enough vitamin D from food and supplements, because elderly people are typically deficient in this nutrient. Supplements with vitamin D have been shown in numerous studies to boost performance in both younger and older adults with low blood levels of vitamin D.
Studies show that vitamin D reduces the risk for sport-related conditions such as stress fractures, total body inflammation, infections, and muscular function. Thus, raising your levels of vitamin D can reduce inflammation, pain, muscle weakness, and muscle-loss myopathy, while increasing muscle protein synthesis, ATP concentration, strength, jump height, jump velocity, jump power, exercise capacity, and physical performance. Vitamin D levels above 40 nanograms per milliliter of blood are required for fracture prevention, including stress fractures. Optimal musculoskeletal benefits occur when vitamin D is higher than 30 nanograms per milliliter of blood but not higher than 50 nanograms per milliliter.
In 2015, medical researchers went to the NFL and collected blood to study the vitamin D levels of 214 athletes among the athletes in attendance. Interestingly, inadequate vitamin D was present in 59 percent of the athletes, including 10 percent with deficient levels. Lower extremity muscle strain or core muscle injury was present in 50 percent of athletes, which was significantly associated with lower vitamin D levels. Athletes who had suffered numerous injuries also showed significantly lower vitamin D levels as compared with uninjured athletes. Even though football players practice outside during the heat of the day in the sunny summer months, they are typically somewhat covered up, blocking the sun’s rays from reaching their skin and raising levels of vitamin D.
There is also a connection between vitamin D and weight management. Vitamin D helps your body better absorb calcium, which has a fat-burning effect. So for calcium to assist in fat burning, your body requires sufficient vitamin D. On the other hand, if the calcium levels in your body are low, a hormone called parathyroid hormone (PTH) and vitamin D increase in response to the shortage and trick your body into thinking it is starving. Consequently, you may pack away more calories in the form of fat and put on extra weight when this imbalance occurs.
Eight Reasons to Pump Up Your Vitamin D
1.Supports bone health
2. Bolsters immunity
3. Boosts mood when taken with the omega-3 fatty acid DHA
4. Assists in neuromuscular control
5. Helps regulate body weight
6. Helps prevent aging-related inflammation
7. Lengthens telomeres (a factor in longevity)
8. Decreases the risk of many chronic and degenerative diseases
