OLDER PEOPLE ARE LESS AFFECTED BY BLUE LIGHT

There has been a lot of recent discussion about blue light and sleep. Blue light is the type of light that we can see outside on a stunning summer’s day, and is also emitted by many phones and tablets. This type of light has been given particular attention because it can suppress the hormone melatonin, which our bodies produce when the Sun goes down to make us feel sleepy (for more on melatonin, turn to p25). Therefore, if we look at the blue light of our tablets late at night, our bodies might be missing a cue that it is time to sleep. The upside of blue light is that it can be helpful at certain times of day, increasing arousal and alertness when needed and helping to set the body clock.

What is less well-known is that the effect of blue light might vary at different stages of life. For example, the lenses of the eyes can yellow over time due to the accumulation of pigment, which can lead to less blue light being passed to our retinas. But before any older adults out there use this as an excuse to play with their tablets in bed, remember that these devices are likely to lead wakefulness and so this is difficult to justify as a bedtime activity.