Sleep, Shift Work, Breast Cancer And Chronotype
I hope you’ve had a great Independence Day weekend and that you’re rested and ready for the new week. For me, it has been great to be back home and have a moment to relax and catch up with family and friends this week.
There were some very interesting stories I found in the research that we can all learn from in the coming week.
Female Lion Chronotypes may have a reduced risk for Breast Cancer.
If you are a Lion then I have some good news for you: A new large scale study suggests that women who are “morning people” aka a LION, may be at lower risk for breast cancer.
Not sure if you are a lion? Take my chronotype quiz and find out, it only takes a second.
In 2007, the World Health Organization’s agency for cancer research labeled shift work a probable carcinogen.
You heard me right, shift work may be contributing to CANCER.
It was commonly believed the cancer risk from shift work was due to environmental factors such as exposure to light at night or other non-sleep-friendly behaviors. However very little has been reviewed when it comes to chronotypes in the shift work population. So far the research has been conflicting with a few studies showing that chronotype does have an effect and several that did not see an effect (when looking at breast cancer).
These studies were not identifying people by genetic markers, in most cases. There is a special technique called Mendelian randomization (MR) that uses genetic variants that are associated with a modifiable risk factor to explore causal effect (translation = there are special statistics that will help us answer this question on a genetic level).
A very large scale study (over 200k) was published this month in the British Medical Journal looking at genetic data using MR to help us understand how chronotypes may have an effect on breast cancer. The authors state:
Findings showed consistent evidence for a protective effect of morning preference and suggestive evidence for an adverse effect of increased sleep duration on breast cancer risk.
So what does that mean for all of my Lions? If you are a LION, this is good news. But, don’t sleep in, it seems to make things worse (but all you Lions already know that)!
Pink Noise while you sleep may help your brain (for all Chronotypes)!
In a new study out this week pink noise (what these researchers called acoustic stimulation which sounds a lot like light to medium rain falling, here’s an example) was seen to help individuals with amnestic mild cognitive impairment (aMCI). aMCI is defined as:
A precursor to the dementia caused by AD is amnestic mild cognitive impairment (aMCI) – a condition of memory dysfunction without impairment in functional independence – which carries a 60–65% lifetime risk of conversion into AD.
There is a good amount of research indicating that sleep disruption is a potential risk factor for the development of aMCI and Alzheimer’s Disease and Dementia. Many of these people suffer from a reduction in slow wave sleep (aka deep sleep or your memory filter) so this type of work is important for all of our brains for sure!
Interesting Fact: Slow Wave Sleep (Deep Sleep) is known as the physically restorative sleep. BUT it also plays a significant role in memory consolidation (meaning slow wave sleep helps you filter out what you do not want to put into your long-term memory). So, having increased slow wave sleep is good for both body and mind!
The study found that if the acoustic stimulation was delivered at night while in slow wave sleep that there was a >10% increase in slow wave activity. This is GREAT for those who are over age 55-60 where we see a decline in slow wave activity and may be a good help for many people in need. Not everyone had improved memory (5/9), but it probably can’t hurt to fall asleep too, or play throughout the night a little pink noise!
That’s all for this week.
I hope everyone had a safe and fun holiday.
Here’s a very interesting article I was interviewed for this week:
Sleeping Pills And Planes: Embarrassing Tales From 35,000 Feet – CNN
from Your Guide to Better Sleep https://thesleepdoctor.com/2019/07/06/sleep-shift-work-breast-cancer-and-chronotype/