Don’t you just love spending some time outdoors, enjoying a walk, filling your lungs with fresh air, letting the breeze caress your skin, and feeling the sun on your face? It’s a simple way to have a change of environment, get in some exercise and recharge.

I get out as often as I can each day, and try to make it at least 20 minutes each time. My sweet doggy, Ginger, gets walked twice daily, in the morning and at the end of the day. I also try to go out for short errands somewhere in between. It really affects my mood and my energy level when I’m cooped up indoors.

In recent years, we’ve been told that too much sunshine can kill. Actually, cancers in general kill far more people every year then skin cancer does. In fact, regular doses of sunlight have been shown to help in preventing most cancers. It is sun-burning, not sun-tanning, that may cause skin cancer. Many people living in urban societies spend an increasing amount of time indoors, in artificial lighting and hooked to the computer. Occasionally, they spend a day here or a weekend there baking at the beach or by the pool, or fry on vacation. Such sporadic and intense exposure to the blazing sun may be compared to taking all of one’s yearly intake of alcohol in a fortnight or so. No wonder sickness may result.

Some decades ago, Dr John Ott investigated the background to a report that children at a school in Illinois had five times the national rate of leukaemia. The schoolhouse was a plain, modern building with very large windows in every room, and all the pupils who developed leukaemia had been in two particular classrooms. In these two rooms the teachers always kept the large curtains completely drawn across the windows to reduce glare and distraction, and to keep the children’s attention on schoolwork. The indoor lighting was therefore on all the time, and this was ‘warm white’ fluorescent. The whole class spent its working day in light of twilight intensity, with no blue or UV light at all except at playtime – and in Illinois they have some hard winters, during which the children might not go out to play at all.

Several years later the two teachers in question left the school, and their replacements kept the classroom curtains open all the time. The lights were also replaced with cool white fluorescent ones, and of course needed to be used less. From then on there was not a single case of leukaemia in the school for as long as Dr Ott followed it up. No other explanation has been put forward for this remarkable mini-epidemic of leukaemia. It started Dr Ott thinking about the possibility of a link between sunlight and cancer.

In 1936, a report in The Lancet by Peller, a US Navy doctor, suggested an inverse relationship between skin cancer and all other cancers. He observed that Navy personnel had eight times the skin cancer rate of the rest of the population, but only forty per cent of the total death rate from cancer. He proposed that the obvious explanation for this was the greater amount of sunlight to which men serving in the Navy were exposed. Nowadays, many naval personnel probably spend their whole working lives at computer consoles, but in 1936 they naturally led an outdoor life and were in the sun a great deal.

Peller made the startling suggestion that by using high intensities of light, either sunlight or ultraviolet from a carbon arc lamp, we should actively induce skin cancers in patients, in order to protect them from other cancers. As cancers go, those skin cancers that have been clearly shown to be related to sunlight have obvious advantages; the most important of these is that they are visible at a much earlier stage, and can therefore be dealt with. In a strange way, if you had to choose which cancer to get, skin cancer would be an excellent choice.

Now, I’m not saying that you should try to get skin cancer in order to eliminate other kinds of cancer. Baking in the sun is a bad idea. However, the fact is that we need the sun’s energy for a wide range of life-giving processes, like the synthesis of vitamin D (a powerful antioxidant) in the skin to improve our absorption of minerals; the triggering of certain enzymes that repair our DNA; the activation of oils on our skin by sunlight to make them antiseptic and protective; the production of hormones in the skin, in response to sunlight, that stimulate our immune system, and a range of other mechanisms that science has yet to explain.

So what are you waiting for? Let some sun shine in your life everyday!