It advised having lunch outside, gardening or hanging out the washing.
Skin cancer rates have experienced a significant increase in recent years and health campaigners have been urging people to limit their exposure to sun without sunscreen protection or clothing.
NOS said that exposure to sun for at least 15 to 20 minutes could benefit bones.
Sunlight produces vitamin D, which is essential for bone strength and low levels could raise the risk of osteoporosis.
"We are not advocating spending lengthy periods in the sun, as too much sun causes skin ageing and melanoma," BBC quoted Professor Roger Francis, from the NOS Medical Board, as saying.
"Furthermore, staying in the sun too long means that the body breaks down surplus vitamin D shortly after it is produced.
"Lying on the beach for two weeks will not top up levels for the rest of the year," he added.
Moreover, simply sitting by a closed window or in a conservatory was not enough, as this did not produce vitamin D.
Caroline Cerny, from Cancer Research UK, which runs its SunSmart campaign to warn people about skin cancer, said the key was a sensible approach.
"The amount of time in the sun required to make enough vitamin D changes from person to person and depends on things like skin type, time of day, time of year, and where you are in the world," she said.
"We all need a bit of sunshine in our lives, but it's important to remember that the amount of sun needed to make enough vitamin D is always less than the amounts that cause reddening of the skin or sunburn," she added.