If you’re not tired, you’re not going to fall asleep. It is perhaps obvious when you think about it, but many of us don’t. We all know we should have 30 minutes of exercise every day but with today’s hectic lifestyle many of us struggle to find the time. Thankfully, for the gym-phobic amongst us with memories of wet and cold cross-country days across the muddy school playing field, exercise needn’t be always about running, or going to the gym. Ever tried digging over a flower bed or veg plot? Gardening can be a great way to achieve an all-body workout. It can also be a low-impact path to being a little bit more active. Some gentle pottering in the garden (beneficial in itself) can lead to other tasks, which leads to more physical exertion, which can only ever be a good thing... But physical exercise is not the only way that gardening can help you sleep at night.
Sleep is hugely influenced by your natural circadian rhythm. Every cell in the human body has a clock that’s controlled by the suprachiasmatic nucleus (SCN) in the brain. The SCN is linked directly to the eyes. Light then, is a key driver to circadian control. Research has demonstrated if you put people into dark places with no external clues to the time of day, their circadian rhythms will become abnormal very quickly. The body needs appropriate exposure to daylight to regulate the body’s responses to help ‘reset’ this clock and keep you “on time”. Many of us spend the majority of the day inside. Light levels in an office, even close to a window, will be far below those of bright natural daylight which is around 20,000 lux. The spectrum of light inside is also quite different. Natural daylight is quite ‘blue’ (5000-6500K) and the body expects a change to more orange/red tones as the day fades to night. This is one of the reasons why ‘screen time’ in the evening isn’t good when you are supposed to be preparing for sleep. The light entering the eyes is too blue for the time of day. Spending the majority of the day inside where light levels are both low (lux levels around 150 are not uncommon) and often in the ‘warmer’ spectrum range (<3000K) is biologically confusing. Getting outside, getting a bit out of breath, and even being a bit chilly, are the best ways to regulate your body clock.
Read more (Oxford Science Blog, University of Oxford website)