How do the seasons affect our sleep? Sleep expert Dr. Neil Stanley explains.
It’s deep dark winter and yet the pressure is on to kick-off new year’s resolutions. You’re feeling tired and not at all like going to the gym! What’s the right thing to do? Science gives us the answer.
I asked sleep expert Dr. Neil Stanley, who told us we’re basically doing it all wrong.
Do we need more or less sleep in winter?
In summer when the days are long, we have a tendency to sleep less. In winter, when it is dark and cold, we naturally want go to bed earlier and sleep more. Sunlight is the major external stimulus that signals to our brains that it is daytime. It only takes a few minutes of daylight to signal that it’s time to be awake, hence why often in summer we wake early. Our sleep need naturally varies with the seasons because of our dependency on light and dark to entrain our body clock.
What about the impact of modern lighting?
Because of electric light and affordable heating we are no longer ‘slaves’ to our biological clock and we are able to be awake at active however dark and cold it may be outside.
This may seem to be a good thing however one theory suggests that one of the reasons that poor sleep increases our desire to consume sugary and fatty foods is that we are eating for the winter that never comes.
Why would we eat more when we sleep less?
In our pre-industrial times we would eat large amounts during the summer when food was plentiful in order to put on weight in the hope of surviving the winter, essentially a time of famine.
Long day lengths signal to the body that it is summer and therefore we should consume more, the problem is that our technological advancement means that our days are ‘long’ all year round and we never experience the ‘famine’ of winter which would help us lose the pounds we have put on, hence we put on weight.
How can we stop this all-year feast and excessive consumption?
A possible solution to this is to reduce the amount of light during the evening, for instance adopting the common Scandinavian habit of using candlelight.
In winter, our bodies naturally sleep more, eat less and shed excess summer weight.
Yet, we do the exact opposite. Dare to do less.
Dr. Neil Stanley has been involved in sleep research for 36 years starting his career at the Neurosciences Division of the R.A.F. Institute of Aviation Medicine. He is the author of How to Sleep Well.