The sunshine vitamin is significant for your bone and brain health, and your heart. Additionally, If you’ve read the previous Sun Index blog post, you’ll know that your vitamin D levels could prevent developing a cold or the flu. The new research suggests it can also make the lungs and heart more efficient and enhance your fitness routine as well.

The new research by Virginia Commonwealth University School of Medicine¹ concludes that people with higher levels of vitamin D tend to be more physically active. Specifically, the study looked at cardiorespiratory fitness, a measure of how efficiently the heart and lung supply oxygen to alveoli to help the muscles during exercise. People with higher cardiorespiratory fitness can exercise longer and harder, and they also tend to live longer and healthier lives. 

For the study, researchers took a comparison of the vitamin D levels and cardiorespiratory fitness levels—measured by a treadmill test of nearly 2,000 U.S. adults ages 20 to 49 who took part in a nationwide study from years 2001 to 2004. They discovered that people in the top quantile of vitamin D had cardiorespiratory fitness levels that were 4.3 times higher than those in the bottom quartile. Each 10-point increase in vitamin D was associated with a 0.78-point increase in VO2 max, the measurement for cardiorespiratory fitness. Even after adjusting for participants’ age, sex, race, body mass index, and health history, fitness levels for those with the highest vitamin D levels were still three times higher than those with the lowest.

The study was observational, so it could not show a cause-and-effect relationship. But the association was “strong, incremental, and consistent across groups,” said lead author Amr Marawan, MD, assistant professor of internal medicine at Virginia Commonwealth University, in a news release from the European Society of Cardiology (ESC). Dr. Marawan said that “This suggests that there is a robust connection and provides further impetus for having adequate vitamin D levels, which is particularly challenging in cold, cloudy places where people are less exposed to the sun.”²

The study notes that vitamin D could potentially affect cardiorespiratory fitness in several ways. For instance, the nutrient has been shown to boost the production of muscle protein and aid in calcium and phosphorus transport on a cellular level. It may also affect the body’s makeup of fast-twitch muscle fibres, “suggesting that vitamin D may improve aerobic fitness,” the authors wrote.

In addition, higher Vitamin D levels are associated with good respiratory health, according to the Vitamin D and respiratory health in the Busselton Healthy Ageing Study,” at the Department of Respiratory Medicine, in Perth, Australia³. Apart from that, Vitamin D is the key element in regulating the amount of calcium and phosphate in the body, thereby maintaining healthy bones, teeth, and muscles. Abnormal levels of the vitamin have been related to respiratory illness and reduced lung function. Immune optimization and impact on lung structure are one of the proposed mechanisms underlying these effects. However, more information is needed to better understand this relationship, especially regarding the role of several staggering factors.

Research shows that vitamin D deficiency is common among Chronic obstructive pulmonary disease (COPD) patients, but no evidence of a link with lung function decline or mortality has been found. Therefore, researchers determined the serum vitamin D levels in 5,106 people of baby-boomer age to study their association with respiratory symptoms, disease, and lung function. A subset of 4,212 also had spirometry (lung function) data, while 2,669 volunteered for an overnight sleep study.

Respiratory symptoms were assessed by questionnaire and included a whistling sound in the respiratory tracts when breathing, shortness of breath, chest tightness, cough, and sputum. Results showed that low levels of vitamin D are related to breathing illnesses such as bronchitis and asthma, and symptoms including wheezing and chest tightness. Furthermore, poor lung capacity, as measured by forced vital capacity, or the total amount of air exhaled after a deep breath, was also related to low levels of the vitamin.

Moreover, indicating its key role in maintaining breathing health, high levels of vitamin D were linked to better lung function, even after considering the factors known to influence its levels, such as fat, a seasonal illness like flu and fever, and other chronic diseases. “The findings in this study coupled with recent studies investigating asthma outcomes and use of vitamin D supplements strengthen the proposed mechanistic relationship between vitamin D deficiency and respiratory disease,” the researchers wrote. “There is emerging evidence that increasing levels [of the vitamin] either through lifestyle or supplementation can reduce asthma symptoms and severity among individuals with inadequate levels,” Siobhain Mulrennan, MD, the study’s first author, said in a press release.

Women under the age of 55 showed the highest spread of blood vitamin D deficiency (less than 50 nmol/L). The overall spread was 8 percent. Approximately 11% of respondents were taking vitamin supplements. A debate is still on as to either a deficiency of the vitamin agitates COPD, asthma, or bronchitis, or if the low vitamin levels result from disease or its treatment. 

“A follow-up study of these same study participants is currently underway which will allow us to investigate longitudinally the effects of vitamin D levels and its relationship to the development of respiratory illness and associated symptoms, as well as other health outcomes associated with aging,” said Michael Hunter, MD, one of the study’s co-authors. Furthermore, the data and DNA samples collected from the study’s co-authors will be used to assess “the genetic factors that influence vitamin D levels and the relationship to lung function and common respiratory conditions such as asthma, [COPD] and bronchitis,” said Alan James, MD, the study’s senior author.

There is no doubt that Vitamin D is essential, and the sun exposure is a simple and easy way to absorb it. However, most people cannot get enough vitamin D from safe sun exposure. That’s why consulting your doctor first is the best choice. The doctors mostly suggest a blood test to find out if you have got a vitamin D deficiency. Then your doctor can advise you about which vitamin D supplement to take and about consuming more vitamin D–enriched foods. You can track your vitamin D intake from the sun exposure, supplements and food by the Sun Index app to make sure your body gets the recommended intake.

The Latest Tech To Meet Your Vitamin D Goals

To make sure your body is producing healthy levels of vitamin D, you can use the latest technology like Sun Index. Sun Index can help you track and log your vitamin D intake from the sun, food, and supplements. Using AI technology, Sun Index will give you personalized recommendations depending on your skin type and clothing to help you get the required vitamin D intake daily to boost your fitness routine. Also, the Sun Index app can track your sun-safe activity.

  1. Marawan, A., Kurbanova, N. and Qayyum, R. (2018) ‘Association between serum vitamin D levels and cardiorespiratory fitness in the adult population of the USA’, European Journal of Preventive Cardiology. doi: 10.1177/2047487318807279.
  2. Antipolis, Sophia (2018) Vitamin D levels in the blood linked to cardiorespiratory fitness, European Society of Cardiology (ESC)
  3. Mulrennan, S., Knuiman, M., Walsh, J.P., Hui, J., Hunter, M., Divitini, M., Zhu, K., Cooke, B.R., Musk, A.W.(.B.). and James, A. (2018) Vitamin D and respiratory health in the Busselton Healthy Ageing Study. Respirology. 2018; 23: 576–582. doi: 10.1111/resp.13239.