Diabetes and the body clock
It’s Diabetes Week here in the UK.
And, I’m ashamed to say that, although I know a number of people living with the condition, including my dear uncle Bob, I hadn’t given it much thought until it popped up on my Facebook feed.
As I started to read more, I realised just how serious – and scary- the condition can be, with over one in ten cardiovascular deaths linked to high blood sugar – Diabetes, increased risk of cataracts and sight loss – Vision Loss and Diabetes, and doubling your risk of depression – Depression and diabetes.
The rise in the number of diagnoses is a real concern, especially for those of us involved the care sector, with teams who work nights at significantly higher risk than those who work during the day, a risk that goes up with the number of night shifts you do – Night Shift Work, Genetic Risk, and Type 2 Diabetes in the UK Biobank. At the same time, according to the British Journal of Diabetes, between one in three and one in four residents of care homes and aged-care (long-term care) facilities are living with the condition. They consider it second only to dementia in terms of its impact on quality of life – Care home diabetes: an important part of community diabetology where high standards of diabetes care are essential.
So what’s that got to do with the lights?
One of the hallmarks of Type 2 diabetes is disruption to the clock genes that keep your metabolism on track. So people living with that condition need more help than the rest of us to keep that vital system on the road.
This classic study confirms that lighting that delivers bright days and dark nights effectively improves insulin resistance and a number of other markers of a healthy body clock in people at risk of developing metabolic diseases – The influence of bright and dim light on substrate metabolism, energy expenditure and thermoregulation in insulin-resistant individuals depends on time of day.
A more recent paper looks at the difference between natural and artificial light. Just one week working by a window (compared to ‘standard’ office lighting at around 300 lux on the desk) is enough to improve glucose control and metabolism during the day, melatonin levels at night and clock gene expression in muscle and bone – Natural daylight during office hours improves glucose control and whole-body substrate metabolism.
Dark nights are just as important – This recent paper in the Lancet, comparing the health outcomes of over 85,000 records from the UK Biobank, suggests that people exposed to light at night are up to 67% more likely to develop Type 2 diabetes than those who sleep in the dark. The same study notes that the difference in diabetes risk between people with bright and dark nights was similar to the difference between people with low and moderate genetic risk – Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation.
Exercise is another way your body ‘tells the time’.
Gentle exercise is obviously good at any time of day, and getting your steps in early in the day is likely to deliver the most sustained benefits for most of us – perhaps simply because you’re more likely to get it done before life gets in the way and it might even get you outside.
But for people living with type 2 diabetes, working out in the morning can cause glucose levels to spike, putting many people off. This fascinating study found that, for this population, high-intensity exercise in the late afternoon delivers unique benefits, not only reducing cortisol levels but also reducing inflammation and improving oxidative capacity (a measure of overall endurance and metabolic fitness.
It turns out that timing and intensity are key to the effects: high-intensity exercise burns carbohydrates rather than fats, just at the time of day when insulin resistance is highest and mitochondrial function peaks – one of the key vectors for metabolic control – Exercise timing and circadian regulation of metabolism in type 2 diabetes.
There’s growing evidence of the link between infrared light exposure and mitochondrial health perhaps one of the reasons that an office with a window had such a rapid and subsantial effect, Another reason to make the most of natural daylight and – when it’s not too hot – find ways to help older adults (and those who care for them) to get outside.
When a butterfly flaps its wings… could it stop a tornado in Texas?
The metaphor, coined by meterologist Edward Lorenz in 1962 to describe the impact of rounding down one number in his weather prediction model from 0.506127 to 0.0506, has sparked a lively debate across the pond about chaos and unintended consequences ever since – The butterfly effect is a real phenomenon—but not how you think.
But their wings are engineered to selectively respond to specific wavelengths of light in some remarkable ways that might just help us reduce our carbon footprint, perhaps even reducing the risk of those tornadoes happening in the first place – Butterfly wing architectures inspire sensor and energy applications.
Butterflies are cold-blooded, so they have to rely on the environment to keep their temperature within a viable range – when they’re basking with wings outstretched, they’re heating up their muscles enough to fly. When you see them turning and raising those giant solar panels, you might notice they’re optimising the angle for shade.
Their wings are covered with a mesh of living microstructures or scales, tuned to soak up heat from the ultraviolet to near infra-red wavelengths generated by the sun. At the same time, to make sure they don’t overheat, those same microstructures re-emit wavelengths in the mid-infrared, bouncing them off and out into space,
Those from cooler climates evolved to give lower mid-infrared emissivity, limiting heat losses, while those from warmer countries have more, with those optical properties changing over the course of the year in response to seasonal shifts in air temperature.
Those beautiful, delicate wings are radiators and air conditioning units at the same time.
I don’t know if the butterflies basking in my mum’s flowerbeds are triggering a tornado in Texas. But if we leverage their natural way with light, we could perhaps reduce the risk of one happening at all – Air temperature drives the evolution of mid-infrared optical properties of butterfly wings.