Sun exposure and vitamin D

How much is enough?

Getting the balance right

The sun is the body’s main source of vitamin D, which helps the body to absorb the calcium that is vital for bones. A lack of vitamin D increases the risk of osteoporosis, a weakening of the bone strength.

On the other hand, ultraviolet (UV) radiation from the sun is also the main cause of solar keratoses which can lead to non melanoma skin cancer. A balance is required between getting enough sun exposure to maintain adequate vitamin D levels and avoiding too much exposure which raises the risk of skin cancer and other kinds of sun damage. So how much is enough?

Regular, small doses of sun exposure

It is difficult to determine exactly how much sun exposure is necessary for each individual. Many variables are at play, such as age, skin colour, latitude, time of day and the time of year. However, as a rule of thumb, 5-10 minutes in the sun, two or three times a week combined with a balanced diet, should offer enough vitamin D. 

For most Australians, adequate vitamin D levels are reached through regular daily activity and incidental exposure to the sun. During summer, the majority of people can maintain adequate vitamin D levels from a few minutes of exposure to sunlight on their face, arms and hands or the equivalent area of skin on either side of the peak UV periods (the middle of the day when UV levels are most intense) on most days of the week

In winter in the southern parts of Australia, where UV radiation levels are less intense, people may need about two to three hours of sunlight to the face, arms and hands, or equivalent area of skin, spread over a week to maintain adequate vitamin D levels. In winter in northern parts of Australia, people will continue to maintain adequate vitamin D levels going about their day-to-day activities, so it is not necessary to deliberately seek UV radiation exposure.