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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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January 01, 2018

Dear Mark: Happy New Year, and Flight Crews, Radiation, and Cancer

By Mark Sisson
22 Comments

Dear_Mark_Inline_PhotoBefore I get to the questions, Happy New Year, everyone! We have some exciting announcements and daily posts coming throughout January designed to help you successfully tackle this coming year (and any future ones you experience) along with some great giveaways, so stay tuned this week.

For today’s Dear Mark, I’m answering just one question. It concerns an article I posted in yesterday’s Weekend Link Love about the radiation exposure flight crews experience. They receive more radiation than people who work next to nuclear reactors, which sounds really dangerous. Won’t all that radiation result in higher cancer rates?

Let’s take a look:

Hi Mark,

Regarding the article about flight crews being exposed to more radiation than any other profession, does this translate into higher cancer rates?

The atmosphere is teeming with cosmic rays from outer space. Few reach us here on the Earth’s surface, but up in the air it’s a different story. Your average member of an air crew will receive about three times as much radiation each year as your average landlubber does.

Here’s the article

So they’re getting considerably more radiation than everyone else. Are flight crew members even at a higher risk for cancer? Maybe, depending on the sex, the study, and the cancer. In one study of female flight attendants, breast cancer and melanoma were the biggest risks. In another, male crew members had slightly increased risks for melanoma and all-cause mortality while female members had slightly increased risks for breast cancer and reduced all-cause mortality and mortality from all cancers. Another study found that female flight attendants reported 34% more reproductive cancers than the general population.

Okay, there are some increase and some decreases. But let’s focus on the increases. Is the radiation the cause?

They do get more radiation than anyone else, and high dose radiation can and does cause cancer.

But that’s not all they get. They also subject their bodies to consistently inconsistent circadian inputs. They whizz all over the world, crossing time zones. They’re often active at night, if their bodies can even identify “night.”

The two cancers that keep popping up—breast and melanoma—have established relationships to circadian arrhythmia. The ability of our skin to resist the damaging effects of UV rays is severely degraded when sleep or circadian rhythms are disturbed. And there are dozens of studies linking breast cancer to shift work, sleep disturbances, nighttime light exposure, and other things that either cause or reflect circadian misalignment.

My guess is that the circadian arrhythmia of plane work is more of a primary cause.

There’s also the lack of sun exposure.

As I’ve shown in a previous post, too little sunlight may be as bad for melanoma risk as too much sunlight. Sun gives us vitamin D, which has the ability to turn pre-cancerous skin cells into benign skin cells, repair UV damage, and prevent the formation of skin cancer. If you’re sitting inside an airport or an airplane for most of your work day, you aren’t producing any vitamin D from sun exposure.

But I don’t think the radiation is having much of an effect. In one study that found an increased risk of skin cancer in pilots, they were unable to link the increased risk to increased exposure to cosmic radiation. Although the authors maintain the “influence of cosmic radiation on skin cancer cannot be entirely excluded,” I find it far more likely that circadian misalignment and perhaps sun deficiency are the culprits. 

What’s really ironic is that the low level doses of radiation flight crews receive may be protective. This is the hormesis hypothesis, which posits that low doses of otherwise harmful stimuli provoke an adaptive response that results in net benefits to health. Most people can think of hormetic stressors like polyphenols (antioxidants are actually pro-oxidants that compel our endogenous antioxidant systems to work better), fasting (going without food trains us to burn body fat), exercise (damages your muscles, which come back stronger than before), but radiation is another one.

That’s probably surprising to you. Radiation is supposed to be dangerous at any dose, just less dangerous at lower doses. Turns out that the old paradigms of radiation toxicity are probably wrong as an absolute anyway.

Linear paradigm: The toxicity of radiation proceeds linearly in a dose-response fashion.

Threshold paradigm: There’s a certain amount of radiation that we can safely tolerate, after which the toxicity increases linearly.

Hormesis paradigm: Some radiation is healthier than none. Too much is really bad.

Imagine if the hormesis hypothesis is true. That would mean it’s conceivable that protecting the flight crews from radiation exposure would increase their risk of cancer. I’m not saying it’s true. We need more data. I’m just saying I wouldn’t be surprised if it were.

All this is a roundabout way of saying not to worry about flying. And if you are a flight attendant or pilot, perhaps you should worry, just not for the reasons you were thinking.

Oh, and get your sleep, sun, and daytime natural light. Wear blue blocking shades after dark and cut down on the electronics usage.

Take care. Have a great year. I can’t wait to tackle it with you all.

TAGS:  dear mark, toxins

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22 Comments on "Dear Mark: Happy New Year, and Flight Crews, Radiation, and Cancer"

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NaturalGirl
NaturalGirl
1 month 23 days ago

Sleep and getting some sun are something I want to do more of this year. I travel extensively and want to rest and enjoy the sunlight a little more than I do. I do turn off all electronic devices several hours before bed. Happy New Year everyone.

Elizabeth Resnick
1 month 23 days ago

Wow, lots to absorb here. I’m not going to worry about the little bit of radiation I’m exposed to when flying…the benefits of travel and new experiences are so worth it. But the whole circadian rhythm thing is really interesting…I’ve really been working on improving mine. I’m trying to avoid looking at my phone when I go to bed (this is tough for me) and maybe it’s time to break out my ugly orange goggles again. Thanks for the great info!

HealthyHombre
HealthyHombre
1 month 23 days ago
A couple of years ago I got a cat scan of my brain (no jokes, they did find one LOL). I later found out it was the equivalence of something like 300 X-rays at one time. I initially freaked out, but what’s done is done. I take a spoonful of chlorella every day, some studies indicate that it protects the body against radiation and removes radioactive particles from the body. There is also some evidence that a combination of lemon balm, ginkgo biloba and spirulina can mitigate the affects of radiation. I also take curcumin, cycle in a medicinal mushroom… Read more »
Shary
Shary
1 month 22 days ago

Radiation is cumulative and exposure should therefore be avoided whenever possible. Unfortunately, the medical profession has long had a cavalier attitude toward this fact. Researchers at U. Penn have found that ordinary flax seed can mitigate harmful effects of radiation in mice, both before and after exposure. Don’t know if it works for humans. You might want to read up.

HealthyHombre
HealthyHombre
1 month 22 days ago

Thanks for the tip Shary, I will research that right away! I do take a tablespoon of ground flax seed every day to help with PSA levels, so maybe I got lucky and someone up there was helping me out LOL. I do agree with your assertion 100%. – George

Ross
Ross
1 month 23 days ago

“But I don’t think the radiation is having much of an effect. In one study that found an increased risk of skin cancer in pilots, they were unable to link the increased risk to increased exposure to cosmic radiation.”

Every been in a cockpit? It’s flooded with sunlight. Pilots don’t just wear those expensive aviators for fun. I’d suggest elevated skin cancers are due to the sunlight exposure at higher altitude which would have an effect on the ratios of UVA, B and C received. Man did not evolve at 40,000 feet.

Nannsi
Nannsi
1 month 23 days ago

+1

Rob H
Rob H
1 month 21 days ago
I found Mark’s POV very thought provoking: I tend to agree that the deleterious effect of disturbed circadian rhythm is going to be pretty significant for frequent flyers. There is a significant body of research now to back this up. I also tend to agree that the quite mild ‘background cosmic radiation’ effect is probably hormetic, ie overall beneficial (see: https://www.ncbi.nlm.nih.gov/pubmed/23304106 and https://s3-us-west-1.amazonaws.com/paperchase-aging/pdf/kLv5jievRxBADM638.pdf ). However, I can also envisage there being an additional deleterious effect of sunlight in the cockpit: the glass will filter out the UVB rays (which are the ones responsible for Vitamin D synthesis), but it will… Read more »
tribal
tribal
1 month 21 days ago

High quality aircraft glass (as found on Airliners) – the windshields are especially thick – UV proof, but not enough. Some pilots actually wear sunscreen – the sunglasses are to reduce glare and block UV, and they also look cool.

Matheus Bitencourt
Matheus Bitencourt
1 month 23 days ago

Hi
Won’t we have the 21-days Primal Blueprint this summer on Vimify?

Thanks and happy new year

Jackie
1 month 23 days ago
Mark, this post sorely disappointed me. I consider you fairly unbiased and thoughtful when it comes to your research. But I have a major problem with how you and the wellness community completely discount the dangers of unprotected UV exposure (a KNOWN carcinogen). Yes, a little sunshine is good for you, but too many people use the vitamin D excuse to overdo it. You max out your vitamin D production in about 10-15 minutes of incidental sun exposure – which you can get on forearms running errands – anything beyond just damages your DNA (look up cyclobutane pyrimidine dimers). I… Read more »
HealthyHombre
HealthyHombre
1 month 22 days ago

Dr. Dosal, just in case you did not already know about this, for your patients that work outdoors, in addition to standard protection techniques, you might want to consider recommending they take an astaxanthin supplement daily. There is compelling evidence it greatly helps protect against sun damage.

Charles-T
Charles-T
1 month 21 days ago

Are you really telling me you don’t believe that pilot’s increase in skin cancers is related to being tens of thousands of miles closer to the sun and UV radiation, and is instead related to their disturbed sleep pattern???

Planes generally fly no higher than 40,000 feet, ( i fly a lot so going on my own experience)
40,000 ft = 7.5757576 miles.

Rob H
Rob H
1 month 21 days ago

I think what Jackie meant was: “flying tens of thousands of miles at 40,000ft”. She seems a very educated woman (+1 to her very intelligent comment above by the way) and I’m sure does not imagine that an aeroplane cruises at an altitude of 10,000 miles+. We would be in space at an altitude 62 miles…

tribal
tribal
1 month 21 days ago

I’ve flown a number of small planes, with glass roof canopies, and believe me, you will get sunburned. Even the super thick Airline windshields let through UV, they designed them primarily for strength – new regulations may see string UV filtering become a requirement. Airline pilots have been known to apply sunscreen as a norm.

Paul and Karen
Paul and Karen
1 month 23 days ago
Just finished reading “Why we sleep” by Matthew Walker. Everything you wish to know about the power of sleep, circadian rhythms, NREM AND REM. For us (personally) it’s the final piece in the jigsaw of health and fitness. To quote from one of his chapters “I was once fond of saying sleep is the third pillar of good health, alongside diet and exercise. I have changed my tune. Sleep is more than a pillar: it is the foundation on which the other two health bastions sit. Take away the bedrock of sleep or weaken it just a little and careful… Read more »
Paul and Karen
Paul and Karen
1 month 23 days ago
Just to add that in reference to your article and again I quote from Matthew Walkers book: “Stirred by the strength of accumulating evidence, Denmark recently became the first country to pay worker compensation to women who had developed breast cancer after years of night shift work in government sponsored jobs such as nurses and air cabin crew. Other governments – Britain for example – have so far resisted similar legal claims…….despite the science”. Radiation may have some effect but disruption to your own natural sleep rhythm appears to be the major cause. According to M Walker companies like Nike… Read more »
Sherryl
Sherryl
1 month 22 days ago

I’m a Flight attendant, and am also wondering about the WiFi we have on the planes now, and how that is affecting us health wise.

OnTheBayou
OnTheBayou
1 month 20 days ago

It’s not. At all. Good lord, you have a hundred times higher dose and duration in your own home. Further, the energy levels of cosmic rays, UV, and UHF (phone, wifi) are very wide.

KetoTed
KetoTed
1 month 19 days ago

I’m a pilot, do what I do. Eat more chicken wings.

Dr M
Dr M
1 month 16 days ago

THERE IS NO EVIDENCE FOR HORMESIS IN RELATION TO RADIATION. THERE ARE KNOWN DOSE-DEPENDENT EFFECTS. THE FACT THAT THEY ARE TOO SMALL TO DETECT IN POPULATIONS WHO LIVE OR WORK AT ELEVATION DOES NOT MEAN THEY DO NOT FOLLOW THE SAME PATTERNS OF THOSE EXPOSED TO RADIOACTIVE WEAPONS OR MEDICAL RADIATION TREATMENTS. The author is clearly not trained as a radiation worker. It’s concerning that you’re speculating about this and raises doubt about the other ideas and claims you make on your website.

Hap
Hap
1 month 16 days ago
Dr M In my journals…including the JNM…the LNT is gasping its last. It is not quite dead but expert opinion is substantially in the upper hand. My RSO is the President of Assoc of Medical Health Physicists…..she and I toss this around a lot she has rejected it. The LNT infrastructure and regulations is being dismantled to some degree . For radiation workers there are still regulations and neither the NRC ior FDA in a position to join the rolling stone too far. If you wish I can dig around link you to the articles and discussion. I oversee the… Read more »
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