According to a study that was presented to a group of endocrinologists at an Edinburgh conference, supplements of vitamin D may improve sports performance and reduce the risk of cardiovascular disease. One of the things vitamin D does is to block the stress hormone cortisol that makes your blood pressure go up. The problem is that many people lack vitamin D, not only in the winter time but even during the summer period.
Vitamin D controls levels of calcium and phosphorous in the blood, which has importance for the bones, the teeth, and the immune system, but it also protects against inflammation, cancer, and many other diseases.
Earlier research reveals that vitamin D blocks the activation of the enzyme 11-ßHSD1, which is necessary for producing the stress hormone cortisol. High cortisol levels cause the blood pressure to increase by making blood vessels constrict and by stimulating the kidneys to retain water. In competitive sport, it is quite natural for the blood pressure to go to ensure an optimal blood supply to the brain and muscles. It is important, however, that the blood pressure does not increase too much, and it must return to normal afterwards. Because vitamin D is able to reduce cortisol levels, the nutrient is likely to improve sports performance and reduce the risk of cardiovascular disease.
Vitamin D supplements lower stress hormones and improve your physical condition
In the study that was presented at the conference, researchers from Queen Margaret University in Edinburgh had recruited 13 healthy adults and matched them according to age and weight. The participants were given either a placebo (dummy pills) or 50 micrograms of vitamin D daily for a two-week period. At the end of the study, those participants who had been given a vitamin D supplement had lower blood pressure compared with the placebo group. Also, they had lower levels of stress hormones in their urine.
Furthermore, an endurance test showed that those who had taken vitamin D were able to bicycle 6.5 kilometers in 20 minutes. Before supplementation, they were only able to bicycle 5 kilometers in the same period of time. Although the group that took vitamin D were able to bicycle 30 percent longer in the same number of minutes, they showed fewer signs of physical exertion.
Lack of vitamin D is quite common - even during the summer
The summer sun is our primary source of vitamin D. For instance, by spending our lunch break outdoors in the sun, dressed in light summer clothes, we can produce around 50 micrograms of vitamin D. The diet only provides a little vitamin D, typically though such things as oily fish and egg yolk. Still, many people get less of the nutrient than recommended, and that amount is far below the amount of vitamin D we can produce ourselves by exposing ourselves to the summer sun.
An estimated 10 million people in England have low blood levels of vitamin D. More specifically, 10 percent of the population is believed to have low vitamin D levels in the summer, and 40% of the English have low levels of the nutrient in the winter period. Because dark-skinned people have greater difficulty with synthesizing vitamin D from the sun than those with lighter skin, as much as 75% of the dark-skinned individuals are believed to be vitamin D deficient. The problem is even more pronounced among those who wear veils. Similar figures are observed in other northern European countries.
|Vitamin D deficiencies are common, and this is primarily because of our modern lifestyle with too little sun exposure during the summer period, the use of sun factor, dark skin, and veiling.|
Sciences' next step with vitamin D for athletes
According to Dr. Raquel Revuelta Iniesta, who co-authored the above mentioned study, supplements of vitamin D are likely to increase a person's physical endurance and reduce the risk of cardiovascular disease and hypertension. The next scientific step is therefore to conduct a large, clinical study over a longer period of time where healthy people and large groups of bicyclists, long-distance runners, and other athletes take supplements of vitamin D.
A vitamin D deficiency is a tacit syndrome with many grave consequences
Lead investigator of the study, Dr. Emad Al-Dujaili, points out that lack of vitamin D is a tacit and insidious syndrome that is also related to insulin resistance, diabetes, rheumatism, and an increased risk of several cancer forms. Therefore, the study shows new aspects of why it is so important to have adequate vitamin D levels in the blood all year round. Evidence suggests that this definitely also applies to athletes who wish to optimize their performance and protect their hearts.
Moderate exercise contra extreme sport
There is no doubt that normal exercise is good for the heart and cardiovascular system. However, extreme sport may be highly harmful, as it can strain the heart and the musculoskeletal system and deplete levels of nutrients in the body. An Australian study has revealed that marathon, ironman, triathlon and other types of endurance sports can lead to permanent heart damage. The question is whether vitamin D levels are a contributing factor.
|It is possible in practice to cover your need for vitamin D if you expose yourself to enough sunshine during the summer period. But in the winter, it is advisable to take a high-dosed vitamin D supplement, especially when you consider that the daily reference intake is far below the body's actual requirement.|
Science News. Vitamin D pill a day may improve exercise performance and lower risk of heart disease. ScienceDaily
Sybille Hildebrandt. Marathon og triatlon skader hjertet. Videnskab.dk
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