Scroll down to watch How To Enable Nightshift. And Read About How Blue Light can Make you Hungry, Tired, and Depressed.
Smartphones emit luminous blue light so you can see the display, even on the sunniest days. However, your brain gets confused by blue light at night, as those azure emissions actually mimic the sun. Makes sense, right?
Turns Out You Your device could be changing your metabolism
UPDATE: This story originally discussed a study done by Ivy Cheung, a doctoral candidate in the Interdepartmental Neuroscience program at Northwestern University in Chicago found that It a single three-hour exposure to blue-enriched light in the evening acutely impacted hunger and glucose metabolism.
The researchers concluded, “Blue-enriched light exposure immediately before, and during the evening meal acutely increases hunger..."
But, a more recent study determined this:
Blue-enriched light exposure acutely altered metabolic function in both the morning and the evening compared to dim light. Specifically, both the morning and evening blue-enriched light exposure resulted in higher insulin resistance relative to dim light. In the evening group, blue-enriched light also led to higher peak glucose compared to dim light, suggesting an inability of insulin to adequately compensate for the increase in glucose at this time of day.
While blue-enriched light clearly altered subjective alertness in the evening, the lack of effect on subjective hunger was surprising considering the findings from a previous study showing changes in subjective appetite with morning bright light exposure . It is possible that, unlike subjective alertness, a single acute light exposure may not be sufficient to illicit changes in subjective hunger. However, repeated daily exposures or exposure while in a natural environment (as opposed to a laboratory setting with controlled food intake and little physical activity) may lead to different outcomes more in line with these prior field-based studies.
There was also no effect of blue-enriched light exposure on hormonal measures of hunger/satiety (leptin and ghrelin). This is in contrast to findings from Figueiro and colleagues  reporting changes in leptin and ghrelin in response to morning red, green, and blue light following sleep restriction (5 hours of time in bed). This difference could be explained by the sleep restriction in their study, while the participants in the current study were given more opportunity to sleep (8 hours of time in bed) prior to light exposure.
In both rodents [11, 33] and humans , daily light exposure patterns are associated with body weight, body composition, and metabolism even after taking caloric intake into account. Given these reports, light’s influence on weight regulation likely involves other mechanisms beyond a potential increase in caloric intake due to changes in hunger/appetite. One possible mechanism is the impact of blue-enriched light exposure on glucose metabolism, as observed in these earlier animal studies and in the current study. The metabolic response to blue-enriched light exposure was quick; within 30 minutes of blue-enriched light exposure onset, HOMA-IR was 30% higher in the morning and 19% higher in the evening compared to dim light exposure. It is plausible that extended or more chronic exposure to blue-enriched light may further impact insulin resistance, given that HOMA-IR is 50–65% higher in the morning with repeated sleep restriction compared to the fully rested state [38, 44]. These changes in insulin resistance with blue-enriched light exposure could, over time, impact feeding behaviors, body composition, and/or body weight.
Don’t Be Blue
Scientists figured out a while back that the timing of blue light exposure was important. In 2014, Researchers at Northwestern University decided to study evening blue light exposure and how it affects hunger, metabolic hormones, and sleepiness.
They studied a group of healthy adults who had ‘regular’ sleep and eating schedules (that, in and of itself, deserves a study!) For 4 days, researchers gave them and compared what happened to these participants when they ate identical meals while exposed to enriched blue light in the evening vs being exposed to dim light.
I’m Hungry. Therefore, I Eat
Turn off the screens so that light has no chance of tweaking your natural hunger. There was a follow-up study on blue light and hunger – See the link below.
More About Blue Light and Your Body
This blue light actually can suppress production of the sleep-regulating hormone melatonin. Bright blue light in the evening hours can throw off your body clock, confusing your brain into thinking it’s still daytime which in turn effects our Circadian Rhythms.
The best way to avoid the blue light from suppressing your melatonin production or disrupting your circadian rhythms is to cut back on using your phones, computers or iPads at night. The National Sleep Foundation Recommends powering down all devices 2 hours before bed. We also offer blue-blocking orange glasses and a blue blocking retina guard for your laptop or phone for when it gets dark.
Meanwhile, Tech Wellness offers another option to battle the blues: Our orange glasses for nighttime wear (also known as blue blockers). A Swiss study examined a dozen teen boys wearing orange-tinted glasses in the evening for a week. The boys reported they felt “significantly more sleepy” as compared to when they wore clear glasses. Similarly, it appears that blue light affects kids and young adults the most, due to changes in the older adult eye anatomy.
Another study we found discussed how blue light exposure effects your metabolism. Studies manipulating morning light exposure are typically associated with leaner body weight, lower boy fat, and altered appetite outcomes. On the other hand, later timing of light tends to be associated with heavier body weight.
Apple to The Blue Light Rescue!
Up until now, iPhone gave you no choice but to abandon your phone hours before bed or stay up to toss and turn–but the recent iOS 9.3 update changes all that. The new Night Shift mode can be set up manually each night at an hour of your choosing (depending on your schedule for that day) or it can be automatic.
When Night Shift sets in, your phone auto-adjusts the screen display, so that it gives off warmer light, with 50% less blue emissions. Blue light signals to the brain to halt a hormone that gives your body the “sleepy time“ prompts.
Good Sleep is a Good Thing
Disrupting the sleep cycle causes a pattern of it being harder to fall and stay asleep—and there’s a slew of serious potential effects on your body for the long-term. Here’s how blue light at night affects your brain:
Disruption of sleep can leave you distracted the next day, making it harder to learn new tasks and disrupt memory. Chronic sleep debt causes neurotoxin buildup. Melatonin levels become suppressed and hunger hormones get disrupted, so people are more prone to depression and obesity, (the latter can lead certain cancers.) Current studies are also being done to examine a link to possible cataracts and retinal abnormalities.
At the very least, these new habits are a pleasant change to your lifestyle and your eyes will feel a little less stressed. Go ahead, try our tips and let us know what you think!
Here's the research