With the ongoing COVID-19 outbreak, athletes have been restricted from outdoor training. This has affected the nutritional status of athletes in various ways, especially with regard to their vitamin D status/level, which is produced in response to sun exposure. Vitamin D is essential for maintaining bone mass, muscle strength and physical performance. It likewise plays multiple other roles in the body, such as helping in calcium absorption and supporting the immune system.¹ Therefore, sufficient vitamin D is indispensable not only for keeping healthy musculoskeletal conditions, but also for improving immune response, especially amidst the COVID-19 outbreak.

Insufficient vitamin D is known as a risk factor for developing stress fractures in military personnel and athletes; low level of vitamin D is also associated with the incidence of muscle injuries. Winter sports athletes have a greater chance of experiencing vitamin D insufficiency as compared to those engaged in spring sports. There is a high prevalence of vitamin D insufficiency among these athletes even in regular situations, resulting in higher risk of stress fractures, illnesses and delayed muscle recovery.²

Serum concentration of 25-hydroxyvitamin D (25-OHD) is the best indicator of vitamin …