Dr. Harsha G N, Consultant- Orthopaedics, Aster Whitefield Hospital

Calcium and vitamin D are the two main elements that build and keep bones strong. While
calcium is obtained through the diet, vitamin D is a must for its absorption in the intestine. If
vitamin D is lacking, bone loss cannot be prevented even with a calcium-rich diet
It’s one of the most frequent health premises that a quick walk early in the morning, when the sun
is out, is sufficient to strengthen your bones and elevate your vitamin D levels. However, experts raise
the point that this widely held belief might be false. The timing of your sun exposure is absolutely
crucial for calcium absorption and bone health and according to research, it is actually afternoon
sunlight that has the most beneficial effects.

Sunlight and calcium absorption
Calcium and vitamin D are the two main elements that build and keep bones strong. While calcium is
obtained through the diet, vitamin D is a must for its absorption in the intestine. If vitamin D is
lacking, bone loss cannot be prevented even with a calcium-rich diet.
The skin produces vitamin D when it is exposed to ultraviolet B (UVB) rays from the sun. The
vitamin D produced then serves to help with calcium absorption. And these UVB rays needed for the
production of vitamin D are at their strongest between 12 p.m. and 3 p.m, when the sun is at its
hottest.

Morning sunlight, between 6 a.m. and 7.30 a.m. is mostly made up of UVA rays, which do not
stimulate vitamin D production in the skin. Early morning sunlight being enough, therefore, is a myth.
To produce vitamin D, the body requires UVB rays, which come from the sun at and after noon.
Therefore, if your intention is to get some sun in the morning to boost vitamin D production, you may
not be benefiting.
How much is needed?

The recommendation is, in moderate weather, to expose the arms, face and legs, for 20 to 30 minutes,
without sunscreen/SPF lotion, two or three times a week. This is usually enough for the body to get
healthy levels of vitamin D. However, long and unprotected exposure to a very hot sun increases the
risk of sunburn and, in some cases, skin cancer or other skin damage, so caution is required.
Balance is essential: being in the right type of sunlight for a few minutes is good for the body, but
overexposure is not recommended.

Why this matters
Osteoporosis, a condition where the bones become weak and prone to fractures, is often seen in
elderly people. In women, it is common after menopause. Of late, however, vitamin D insufficiency
and early bone loss has been detected in young women as well. A lack of physical activity, an indoor
lifestyle, an unhealthy diet, and barely any exposure to sunlight are mainly responsible for this
phenomenon.

In the case of younger adults, lack of vitamin D leads to osteomalacia — a condition that softens and
makes the bones fragile. The trend being seen now is of IT workers and urban women who spend
most of their times indoors, being affected the most.
What about supplements?

Although vitamin D and calcium supplements are quite easy to obtain, self -medicating is not
recommended. Vitamin D alone may not be enough; calcium may also be required. It is best to get
tested and then taken supplements, if prescribed, under a doctor’s supervision.
If you have been aiming to get your body its daily dose of sunshine in the morning, it is perhaps time
to change plans. One of the easiest and most reliable methods to prevent your bones from giving in to
premature wear and tear is to expose yourself briefly and safely to afternoon sunlight, while being on
a well-balanced diet and ensuring regular physical exercise.
So if you want your daily dose of sunshine, make sure you get it when the sun is cooperating with
​‍​‌‍​‍‌​‍​‌‍​‍‌you.