The link between sunlight, inflammation and depression

I was utterly fascinated by BBC 4s Start the Week last Monday ‘In search of happiness’  and have added two books to my must read list as a result.

The first is Chasing the Sun by science journalist Linda Geddes.  It’s about the extraordinary significance of sunlight and how it affects our physical and mental wellbeing.  I’m sure most of us know about sun exposure and vitamin D for healthy bones and immune system, the link between the winter months and depressed mood (SAD), and the importance of getting outside during daylight hours to boost our serotonin and melatonin production and help improve our mood, appetite and sleep.   But did you know:

  • The astonishing difference in lux (the measure of light intensity) between being indoors and outdoors? Apparently it’s at least ten times brighter outside even on a grey day – Geddes quotes 200 inside compared with 2,000 outside.
  • The importance of daylight – and darkness – for our circadian rhythm (you probably did know this);
  • That Florence Nightingale recommended fresh air and sunlight in hospital wards to disinfect them as well as to help patients’ mood and recovery;
  • The cult of sunlight for health and wellbeing in the 1920s, which fell out of favour with the introduction of antibiotics, but is now making a revival as the effectiveness of antibiotics decreases?

Geddes book synopsis also entices me by talking about the ancient solstice celebrations and ‘what the Amish know about sleep that the rest of us don’t’.  I’ll let you know once I find out.

The other book is The Inflamed Mind by Professor Edward Bullmore.  It reveals the breakthrough new science on the link between depression and the inflammation of the body and brain.  The old cartesian dualism of mind and body being separate is no longer valid (I wish I’d had this information for my philosophy degree). Mind, body and brain are all interlinked and inflammation in the body can change the way our nerve cells handle serotonin thereby directly affecting our mood.

Bullmore’s argument is that we need to look more closely at our immune system in the treatment of depression.  If it’s true that, worldwide, depression will be the single biggest cause of disability in the next twenty years, unlocking the link between inflammation and depression is imperative.

Happily for us Nordic walkers, we are physically active and outdoor based.  All that fresh air and exercise will improve our mood, stress levels and sleep.  Plus make us more inclined to sit down with a nice hot drink and a good book.