Night Shift Work May Raise Diabetes Risk

Night Shift Work May Raise Diabetes Risk

Story at-a-glance -

  • Working the night shift increases women’s risk of type 2 diabetes
  • Working a night shift periodically for three years increased diabetes risk by 20 percent, and this increased to 58 percent among those who worked the night shift for 20 years or more
  • Irregular sleep-wake cycles may interfere with your body’s blood-sugar metabolism, leading to insulin resistance and increased blood-sugar levels, both of which are linked to diabetes
  • If possible, avoid night shift work to protect your health. If you can’t avoid it, keep to a schedule so your body’s clock will eventually adjust to your sleep/wake cycle
  • When sleeping during the day, it’s important to keep your bedroom as dark as possible to simulate nighttime. Your body releases important hormones in response to exposure to light and darkness

By Dr. Mercola

One of the worst things you can do to disrupt your body clock is engage in regular night shift work.

However, one-fifth of the work force endures a night shift at least occasionally, and research is now suggesting that this could be one of the culprits behind rising rates of type 2 diabetes.

I realize many people may not be able to avoid night shifts once they've chosen certain professions, but it is vital to understand that when you regularly shift your sleep patterns, you are in fact seriously compromising your health and longevity—in more ways than one.

Working the Night Shift May Increase Your Diabetes Risk Nearly 60 Percent

In a study of nurses, researchers from the Harvard School of Public Health revealed that a woman's risk of type 2 diabetes rises according to how many years of night-shift work she has completed.

Even working a night shift periodically for three years increased diabetes risk by 20 percent, and this increased with time.

Researchers wrote in PLoS Medicine:

"The increase in type 2 diabetes risk associated with night shift work ranged from 5% in nurses who'd worked that schedule for one or two years to 58% in those who'd done so for at least 20 years."

As you probably know, the physiological functions of virtually all organisms are governed by 24-hour circadian rhythms. When your circadian rhythm—which acts like a built-in time-tracking system—is disrupted by late-night artificial light exposure it can have a profound influence on your physical and mental health and well-being.

For starters, your circadian rhythm impacts your body's release of metabolic hormones that regulate satiety and hunger. For example, when you are sleep deprived, your body decreases production of leptin, the hormone that tells your brain there is no need for more food. At the same time it increases levels of ghrelin, a hormone that triggers hunger. This can actually make you gain weight, which raises your diabetes risk.

Further, irregular sleep-wake cycles can also interfere with your body's blood-sugar metabolism, leading to insulin resistance and increased blood-sugar levels, both of which are linked to diabetes.

As researchers explained:

"The increased risk of type 2 diabetes associated with rotating night shift work is also consistent with previously reported positive associations of rotating shift work with obesity and/or weight gain, metabolic syndrome, and cardiovascular disease.

There are several potential mechanisms underlying this association. First, a wide range of biological processes are regulated by the circadian rhythms, including sleep-wake cycles, body temperature, energy metabolism, cell cycle, and hormone secretion. Rotating night shift work is generally associated with chronic misalignment between the endogenous circadian timing system and the behavior cycles.

This circadian misalignment has been found to result in adverse metabolic and cardiovascular consequences, including a decrease in leptin, an increase in glucose and insulin, an increase in mean arterial blood pressure, and reduced sleep efficiency."

Past research has also suggested that disruption of your circadian rhythm could also contribute to diabetes by impairing your pancreas' ability to deliver insulin.

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Your Body is Hard-Wired to Sleep at Night

Human beings have naturally been sleeping during the nighttime for eons, and as a result your inner timekeeper is extremely sensitive to, and actually is controlled by, exposure to light and darkness.

One main role of your brain's pineal gland is to produce melatonin, the natural sleep hormone that plays a vital role in your normal sleep function. Normally, your brain produces melatonin in a daily rhythm that peaks at night, around 9 or 10 p.m. This makes you sleepy, and it is these regularly occurring secretions that help regulate your sleep cycle.

However, if there is even the tiniest bit of light in your room it can disrupt your circadian rhythm and your pineal gland's production of melatonin. If you're awake at night when your body expects you to be sleeping, your body may produce less melatonin.

Melatonin is an antioxidant that helps to suppress harmful free radicals in your body and slows the production of estrogen, which can activate cancer. When your circadian rhythm is disrupted, you therefore may have insufficient melatonin production, which can set you up for:

Reduced ability to fight cancer

Decreased immune function

Accelerated cancer cell proliferation and tumor growth (including leukemia)

Blood pressure instability

Decreased free radical scavenging

Increased plaques in the brain, like those seen with Alzheimer's disease

Increased risk of osteoporosis

Diabetic microangiopathy (capillary damage)

If you are interested in finding more information on this subject, I highly suggest reading Lights Out: Sleep, Sugar, and Survival by T. S. Wiley and Bent Formby. The authors believe it is the disruption of normal cycles of light exposure, not what we eat or whether we exercise, that is the primary cause of obesity, diabetes, heart disease and cancer. I think there are many other factors contributing to these health problems as well, but impaired sleep is certainly a large contributor.

Tips for Quality Sleep if You Work the Night Shift

If you currently work nights, I would strongly suggest trying to switch your hours, or at the very least restrict your night shift duty to a couple months at a time. This will at least give your body a chance to readjust in between.

If it is not possible for you to avoid working the night shift, you can somewhat counter the health effects by keeping to a schedule. By being consistent, your body's clock will eventually adjust to your sleep/wake cycle, and this is LESS damaging than if you constantly change shifts and expect your body clock to adjust.

Next, although day sleeping makes it much more challenging to create a dark environment, it is essential that you make your bedroom pitch-black, even if you're sleeping at noon, as exposure to light squelches the production of melatonin. Even the dim glow from your clock radio could be interfering with your ability to sleep -- and more importantly, your long-term health and risk of developing cancer or other health problems.

To get your room as dark as possible while you're sleeping, consider taking the following actions:

  • Install blackout drapes
  • Close your bedroom door if light comes through it; if light seeps in underneath your door, put a towel along the base
  • Get rid of your electric clock radio (or at least block it's light while you're sleeping)
  • Avoid night lights of any kind
  • Keep all light sources off (even if you get up to go to the bathroom) -- and this includes your computer and TV

A Healthy Sleep Routine is Essential for All

Whether you sleep in the daytime or at night, a bedtime routine can help you wind down and prepare for sleep. You should avoid watching TV or using electronics for about an hour prior to going to bed, as it is too stimulating to your brain, making it more difficult to "shut down" and fall asleep.

Instead, try spending this wind-down time doing something that soothes and relaxes your mind. You may want to spend time journaling, meditating, sipping herbal tea, washing your face, or reading a calming or spiritual book.

You can find my comprehensive recommendations and guidelines to help improve your sleep in my article 33 Secrets to a Good Night's Sleep. If you're having trouble sleeping, this is the place to look to get your sleep back on track. Here are five tips from the article to get you started:

1. Keep the temperature in your bedroom no higher than 70 degrees F. Many people keep their homes and particularly their upstairs bedrooms too warm. Studies show that the optimal room temperature for sleep is quite cool, between 60 to 68 degrees. Keeping your room cooler or hotter can lead to restless sleep. When you sleep, your body's internal temperature drops to its lowest level, generally about four hours after you fall asleep. Scientists believe a cooler bedroom may therefore be most conducive to sleep, since it mimics your body's natural temperature drop.

2. Check your bedroom for electro-magnetic fields (EMFs). These can disrupt the pineal gland and the production of melatonin and serotonin, and may have other negative effects as well. To do this, you need a gauss meter. You can find various models online, starting around $50 to $200. Some experts even recommend pulling your circuit breaker before bed to kill all power in your house, or at least shutting off the fuses in your bedroom.

3. Move alarm clocks and other electrical devices away from your bed. If these devices must be used, keep them as far away from your bed as possible, preferably at least 3 feet. Remove the clock from view. It will only add to your worry when you stare at it all night... 2 a.m. ...3 a.m. ... 4:30 a.m.

4. Avoid using loud alarm clocks. It is very stressful on your body to be suddenly jolted awake. If you are regularly getting enough sleep, an alarm may even be unnecessary. I gave up my alarm clock years ago and now use a sun alarm clock, which has a special built-in light that gradually increases in intensity, simulating a natural sunrise. It also includes a sunset feature where the light fades to darkness over time, which is ideal for anyone who has trouble falling asleep or if you work the night shift and want to simulate a sunset during the day.

5. Reserve your bed for sleeping, and consider separate bedrooms. If you are used to watching TV or doing work in bed, you may find it harder to relax and drift off to sleep, so avoid doing these activities in bed. Recent studies also suggest that, for many people, sharing a bed with a partner (or kids, pets) can significantly impair sleep, especially if the partner is a restless sleeper or snores. If bedfellows are consistently interfering with your sleep, you may want to consider a separate bedroom.