Your body makes a hormone called melatonin (often called the “sleep hormone”), in the pineal gland in your brain, in response to light exposure and is directly linked to when we should be awake or asleep – this is your circadian rhythm.
Melatonin however affects not only sleep but may also have a role in mood, inflammation, brain ageing conditions, immune function, weight control, seasonal affective disorder and diabetes. Sounds important!
Bright sunlight boosts melatonin levels and as the day starts to turn to night, the pineal gland releases that melatonin. A good level of melatonin will last about 12 hours which in reality is from around 6pm to 6am. There is a direct correlation between higher melatonin levels (released at appropriate time) and sleep. If you don’t expose your eyes to bright light during the day (as in you wear sunglasses at absolutely every opportunity), then your body quite possibly has lower melatonin levels than it needs, leading to your sleep being impacted. Sunglasses are important to protect our eyes (just like sunscreen protects skin), but we do need exposure to natural sunlight. Just be smart about it.
Melatonin levels are also affected by shift work, some medications and time zone changes (heard of jet lag?).
So what is the take-home from this? If you are having trouble sleeping, one of the easiest things you can try is going without sunglasses sometimes during the brightest times of the day. This may not be your problem – but isn’t this worth a try??