Tag: Medical

I’ve previously touched base on Circadian Rhythm in Geeking Science: Internal Clocks (Oct 18, 2018). The rhythm of our planet, the heartbeat of our existence, driven by the turn of the planet and how and when sunlight hits us. Will we be able to function on any other planet? And if so, how?

In answer to that, scientists have been looking to the sea, deep into the sea where the sun doesn’t shine. How do creatures without light keep track of time? Can we learn how to use their chemistry and genetics to help us? The biological rhythms of deep-sea mussels seem to be related to tides (Mat), which won’t help us much on planets without a sister planet providing a gravity-driven clock alternative. Other deep-sea beasties seem to react to seasonal water changes between heat and cold, modifying feeding behavior to match availability of food sources. Many water animals combine diurnal (light) and tidal (gravity) cycles.

Humans work on a 24.15 hour clock, with some people having rhythms shorter and some longer, but the average is a little longer than 24 hours and resets with sunlight. (Naked Scientists) The longer-than-24-hours allow humans to adjust to the slow increase of the day during the spring and summer, when we need to function well to gather food, and “more recently” (by evolutional standards) to plant and maintain crops. Though based on circadian studies, fighting the natural lengthening of day our bodies are built for likely increased immunity issues during the winter, but the evolutionary trade-off for better and quicker access to food, providing weight gain in preparation of winter, won the day on average for humanity. The outliers provide bonuses other ways as they always do. Even so, SUNLIGHT resets the clock with precision daily so the slight difference either way from the cycle impact is minimal (but enough to have created a genetic preference over the entire species).

But in space, sunlight won’t be guaranteed, so we need information about how to survive without our special Sol-provided sunlight.  The problem is most of the creatures and plants available for us to study here on Earth evolved from the same single-celled creatures billions of years ago which lived on light flowing into the waters. To answer our questions, scientists must find creatures which didn’t derive from this united genetic line or creatures which have managed somehow to mutate away from it.

Japanese scientists recently found a species of jellyfish which work on what looks like to be a 20-hour cycle. (Starling) They do have a diurnal component related to sunrise, but in the absence of a day-night cycle, the species functions on a 20-hour cycle. (Like when humans don’t have access to a light reset, we slowly move off a perfect 24 hours since we are set up to run slightly longer.) They are studying the hormonal differences between this species and other closely related species which operate much more strongly on the day-night cycle.

The more we learn about other creatures, the more we understand ourselves. The blue light keeping us up at night. How food and gravity interact with hormones to support the normal rhythm, or oppose it, creating health problems.  How it controls our sleep and our body temperature. How time of day impacts the effectiveness of medications and our ability to perform physical activities on the job and during recreation.

Some people do much better with night jobs than others. Others have serious issues with seasonal depression as light fades. Closer to the equator, where day-night cycle varies little (and matches where humans originally evolved), the circadian rhythm functions like…clockwork. Toward the poles where the sun might not rise or set for days, humans function less well, mentally and physically.

The rhythms of day-night, moon gravity position, seasons all impact us making us happy and grumpy, awake and tired, healthy and ill. Our internal clocks change as we age from birth through old age. And we must learn how these cycles work if we are going to recreate them elsewhere without our sun, moon, and Earth spinning through our solar system.

In the meantime, if it is late, whoever is reading this, turn off the lights and give yourself a couple hours off-screen to let your sleeping cycle kick in properly.

 

Bibliography

Cleveland Clinic. “Circadian Rhythm.” 2024 March 14. https://my.clevelandclinic.org/health/articles/circadian-rhythm – last viewed 5/11/2026.

Louis, Victoria and Patrick Emery. “Biological rhythms: In the sea, two clocks are better than one. 2025 June 23. https://www.cell.com/current-biology/abstract/S0960-9822(25)00596-2 – last viewed 5/11/2026.

Mat, Audrey M. et al. “Biological rhythms in the deep-sea hydrothermal mussel Bathymodiolus azoricus” nature communications. 2020 July 10. https://www.nature.com/articles/s41467-020-17284-4 – last viewed 5/11/2026.

Naked Scientists, The. “Why is our circadian rhythm not 24 hours?” 2017 August 8. https://www.thenakedscientists.com/articles/questions/why-our-circadian-rhythm-not-24-hours – last viewed 5/11/2026.

Starling, Marlowe. “The Jellies That Evolved a Different Way to Keep Time.” Quantamagazine. 2026 March 20. https://www.quantamagazine.org/the-jellies-that-evolved-a-different-way-to-keep-time-20260320/ – last viewed 5/11/2026.

By Francesca Puledda, Christoph Schankin, and Peter J. Goadsby – https://www.neurology.org/doi/10.1212/wnl.0000000000008909, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=162966149

 

Visual snow is an interesting phenomenon. It can be black and white dots over a field of vision (visual static). It could be excess floaters. It could be color flashes. When some people close their eyes, they only see dark; I see a light show. Sometimes it leaks over into my normal vision. If I am excessively tired, especially after too much screen time, the black and white dots come out to play. When I wore contacts, floaters were constant and even know if I go looking for them, two or three are always hanging around. The color flashes are migraine related, so, thankfully don’t show up often for me. If it is extremely dark, I really get the black-and-white grid strongly as my eyes try to see something no matter how dark it is.

Doctors believe the underling mechanism to visual snow is excessive excitability of neurons related to vision. If so, my neurons light up like a disco ball. On the plus side, my experience with visual snow doesn’t negatively impact my life. It is also highly related the the thinness of my cornea because of extreme nearsightedness my entire life (thanks, Grandma for those genes).

Imagine my surprise to discover most people see dark when they close their eyes. I really thought everyone got after-images and flashes and floaters at least when the eyes closed.

As with everything, there is a spectrum. At the other end from the closed eyes actually showing black is Visual Snow Syndrome – when the light snow never ends even when the eyes are opened. At present, there is no cure, though the medical community, having recently named the VS Syndrome in 2025, are looking into ways to relieve those people experiencing phenomenon to the point it negatively impacts their lives. They can’t see to drive in some cases…or read…or embroider (horrors!).

The Syndrome is defined as Visual Snow (or similar symptoms like floaters) that persists for more than three months and has no other known cause (like excessive thinning of the cornea because of nearsightedness, lack of sleep, or migraines). For some people, anxiety has created the issue and with decreasing the stress, fixes the issue. Overall it is tinnitus for the eyes. Instead of the ear hearing sounds not there, the eye sees things not there. And, just like tinnitus, it can vary between annoying and overwhelming.

Closing recommendation: Anytime you experience sudden changes of vision, get it looked into immediately. Sometimes they can do nothing; sometimes they can repair a retinal tear can save your vision. Do no delay if floaters suddenly increase, you get the Visual Snow where you never had it before, or blind spots. Some things you can rub dirt in them and walk them off; do not do this with your eyes.

 

Bibliography

Cleveland Clinic. “Visual Snow Syndrome.” 13 November 2022. https://my.clevelandclinic.org/health/diseases/24444-visual-snow-syndrome – last viewed 2/10/2026.

Medical Centric Podcast. “Visual Snow Syndrome: Everything You Need to Know.” 2022. YouTube: https://www.youtube.com/watch?v=E8HrgFdh9Lc – last viewed 2/10/2026.

Visual Snow Foundation, The. (website) https://visualsnowsyndrome.com/ – last viewed 2/10/2026.

Wikipedia. “Visual Snow Syndrome.” Undated. https://en.wikipedia.org/wiki/Visual_snow_syndrome – last viewed 2/10/2026.

A Facebook friend share with me a picture with the following words: Just learned that 80% of organ donors are women and 70% of receivers are men and now I think I might remove myself from the donor program because WTAF (what the ACTUAL fuck).

This is a truly troubling set of statistics if true, as women are 51% of the population and men are 49% (Census – 2010, 50.9% female) and donors and recipients should match the population…or should they?

Time for a statistical dive into organ donations!

First question, is the meme even true? Some meme are just pieces of information created – like if I said, memes accurately quote scientific articles 35% of the time…I just made it up, but it sounds true.

First hit on the google search: “The 2021 report from the National Organ and Tissue Transplant Organisation (NOTTO) reveals a troubling gender disparity in organ donation: 80% of organ recipients were men, while 75% of organ donors were women.” (Anagha) Now, Organisation (with an “s”) indicates this isn’t an American group – this report is from a national-level group answering to the Ministry of Health and Family Welfare in New Delhi, India. The numbers also don’t align with the original meme, but seeing how things work in another country can be helpful with a look into America. This statistic is interesting: In India, 27.7% of all living donor transplants are spouses, but 87% of the spouses doing the donation are the wives. (Anagha)

Even in Switzerland, for living kidney donors, 22% are women donating to their partners but only 8% are male. In the US and Germany, the ratio in both countries is wives donate to partners twice as often as husband to their wives for kidney donations. If you look at the Switzerland numbers, they could also be easily described as two-to-one ratio as well.

I’m not finding information with either the original numbers of the meme, nor information from America, but that still doesn’t mean the mean isn’t true, especially when reviewing how common this disparity is in around the world.

Second step, what are the statistics we need to look at? This isn’t just one statistic being presented, it is two: gender differences in donors and gender differences in receivers. More men than women receive, and more women than men give. Do men need the medical treatment more than women? Are women in a better position to donate than men? These two statistics need to be broken apart if they are to be studied properly.

I think figuring out the recipients will be simpler, so let’s start there.

Third, breaking out the first of the statistics, why do men receive more organ donations than women?

Well, what are the organ donations that people need? We get a hint that Kidney is going to be a be a big one based on the first hit which had statistics from four different countries on the rate of living donations for kidneys. Everyone hears about heart and lung donations, but over 85% of the people waiting for a donations are waiting for a kidney donation – and that is one of the few donations which can have a living donor! Still matches need to be made. The list of organs waiting on donation as of July 30, 2026 in order of amount: Kidney (84.8%), Liver (7.8%), Heart (3.6%), Kidney & Pancreas (2%), Lung (0.8%), Pancreas (0.7%), Heart & Lung (0.03%), plus “other” (0.1%). (HRSA)

So the biggest category on the waiting list BY FAR is Kidney. Do men have a higher rate of kidney disease than women? Because if they do, the 70% of receivers could be explained by a simple rate of disease impact. According to the NIH, the National Institute for Diabetes and Digestive and Kidney Diseases, 1 in 7 US adults have chronic kidney disease, with the chronic version being slightly more common in women (14%) then men (12%). (NIH)

Oh, that is a problem, if more women then men have kidney disease. Reading deeper, I found a VERY important statistic: For end-stage kidney disease where 68% are on dialysis, men are 1.6 times more likely than women to be in end-stage. I hate when they don’t give us equivalent statistics to work with; it is like they are deliberately hiding data. But if this is the case, the split between men and women in end-stage is about 60-40, I think, if I am interpreting their number right. (NIH)

That is HUGE! With 70% of the organ donation recipients male, and 85% of all organ donation kidney, and 60% of the kidney needs male – that explains at least some of the discrepancy right there. If a similar carries over the statistic applying to all the organ needs, then the natural split of organ recipients should be 60% male to 40% female, not the natural 50-50 one would expect by population or the 70-30 which is actually happening.

More details – 46% of those in end-stage kidney disease AND put on the waiting list receive a transplant within five years. Children (under 17) are the most likely at 85% – again, kidney can be done by living donors so family members are move likely to get tested for a donation when a child is involved. Most of the children donations are likely (no indication though is given, so this is a guess) from the adults around them. Females on the list are 47% likely to get a transplant while men are 45% likely to get a transplant.  (NIH)

That is interesting; no indication is given about number of males versus number of females on the transplant list but statistically once on the list there is about an equal chance of getting the needed donation.

So it is looking like the bias is not getting the surgery, it is getting on the list in the first place. Which is likely a combination of referral for treatment and then consideration of the extremity of the disease, both of which the medical community has shown as measurable statistical deviation against women. In fact the Sowinski conference report states “Women may be less likely to be perceived as transplant candidates and are referred less often.” Complicating that also is “Women may have family and other obligations that prevent completion of the evaluation process.” So they are less likely to be referred for treatment, less likely to follow the testing requirements, and less likely to be approved for transplants.

But does this statistic cross to other donations?

A little search, I found an article about sex differences in heart transplants by Chung et al. Only 25% of the candidates for heart transplant are women, with a matching overall number in recipients. Again, it looks like if a person can get on the waiting list, they get the help they need regardless of gender. The challenge is getting on the list. The challenges women face in the heart, again is diagnosis, testing, and referral.

Solution to Recipient Problem: The problem isn’t the transplant waitlist, but the system to get on the waitlist. The medical community is working on being more aware of the male bias baked into the system. More testing and studies need to be done for women, doctors need to be aware of the bias they bring to the door, and accommodations need to be made for the different social roles women usually serve, such as primary caregiver to children and elderly adults. The medical community knows of these issues and are working on it. The 70%-30% recipient of transplantation is just one of the many symptoms. Hopefully time will reduce this problem; but this is one of the statistics to use as a rubric of success in reduction and eventual elimination of gender bias within the medical institution.

Fourth, the second statistical question, why do women donate more than men? And how can that be fixed to?

First, indication of why there is a difference is that statistic of 85% of children get a kidney donation. The statistic of donation does not break out living donations versus deceased donations. Here is a matching interesting statistic – women do 33% of their donations between the ages of the 35 and 49 (Ruzicka). One in three of their donations, living and deceased, happen after the major child-bearing years but before their children are fully grown. The mother already gave her body to her child, giving up a kidney to keep them alive (if compatible) is a natural consequence.

In fact, over 60% of the donations for women happen during the child-caretaking years. Men on the other hand donate as children (22%) or 18-34 (22%); around age 30 is when the ratio of men to women changes. More men than women are born, but overall, there are more women than men. This is because before age 30, males die at a higher rate than women by accident (trauma) and disease. Men donating more at the earlier ages likely aren’t living donations but deceased donations.

Yee shares that while the vast majority of living organ donors are women, only 40% of the deceased donors are women.

So when women are alive to be pressured into donating for family and spouses, they do so, whereas men donate after dying from trauma. This can be a problem, especially in the heart and lung situation where size can impact who can receive the donation. In addition, some transplants do seem to have some minor gender benefits for like-to-like matches, so having men being the deceased donors by a 60-40 ratio reduces some of the donation effectivity for women – decreasing their chances of receiving a donation.

Solution to the donation problem: One, get men and women to sign up for deceased organ donation, and make sure the family is aware of the person’s wishes. 10% of all families refuse to consider organ donation, and the majority of the rejections were for females who passed. (Yee) Organ donations discussions need to happen in advance of the emergency.

Two, men need to participate in the living donation for the kidney and the partial liver at the rates women do. That is really where the discrepancy in donation is happening. Not on the slab, but in the home. Don’t pressure the females; everyone in the family should be tested.

It isn’t that the women are doing too much, it is men aren’t doing enough. And it can be done while living.

IN CONCLUSION

Organ donation and organ transplantation are a complicated multifactorial situation impacted by multiple society and culture circumstances. A simple meme giving two stats hardly covers the consideration the conversation deserves. Remember this when facing other 15-second meme lore drops.

Also, if you haven’t signed up for organ donation, do so, and let your family know your wishes.

 

Bibliography

Anagha BP. “Gender disparity in organ donations: She gives, He received.” Change in Content. 2024 October 14. Last viewed 8/16/2026. https://www.changeincontent.com/gender-disparity-in-organ-donation/

Census. “Quick Facts.” www.census.gov. page for April 1, 2010 data. Last viewed 8/16/2026. https://www.census.gov/quickfacts/fact/table/US/LFE046224

Chung, Alice; Heidi Hartman & Ersillia M. DeFilippis. “Sex Differences in Cardiac Transplantation.” Springer Nature Lin. 2023 December 07. Last viewed 8/16/2026. https://link.springer.com/article/10.1007/s11883-023-01169-0

HRSA – Health Resources & Services Administration. “Organ Donation Statistics.” Last viewed 8/16/2026. https://www.organdonor.gov/learn/organ-donation-statistics

NIH – National Institute of Diabetes and Digestive and Kidney Diseases. “Kidney Disease Statistics for the United States.” Last viewed 8/16/2026. https://www.niddk.nih.gov/health-information/health-statistics/kidney-disease

Ruzicka, Emilla. “Who is most likely to donate organs in the US?” Northwell Health. 2023 April 24. Last viewed 8/16/2026. https://www.northwell.edu/news/the-latest/how-the-demographics-of-organ-donors-differ-by-state

Sowinski, Deirdre, et al. (It’s over ten names, look it up) “Addressing sex-based disparities in solid organ transplantation in the United States – a conference report.” American Journal of TRANSPLANATION. Volume 23, Issue 3. 2023 March. Last viewed 8/16/2026. https://www.amjtransplant.org/article/S1600-6135(22)24785-6/fulltext

Yee, Erika, et.al. (Erika Yee, BS; Seyedeh Maryam Hosseini, MD; Bianca Duarte, BS; Shannon M. Knapp, PhD; Molly Carnes, MD, MS; Bessie Young, MD, MPH; Nancy K. Sweitzer, MD, PhD; and Khadijah Breathett, MD, MS) “Sex Disparities in Organ Donation: Finding an Equitable Donor Pool.” Journal of the American Heart Association. 2021 September 24. Last viewed 8/16/2026. https://www.ahajournals.org/doi/10.1161/JAHA.121.020820