View Full Version : If Days Were Longer, Would We Age Slower?

Margarita Skies
11-24-2010, 09:25 AM
I know this is an awkward question and that people would only be able to give their opinions to this because no one knows for sure, but it's a question that just occurred to me to ask and i wanted to know your opinions on this. What do you think? If days were longer than 24 hours, say 48 hours long, would we age more slowly or at the same rate? I didn't know what forum to post this in, so mods, feel free to move it anytime. I am working on a novel series where I am thinking of making Earth days longer than they are so my characters could do more things during the day, especially those that work the hardest. That's why I have to have some opinions on this.

Best regards.

Susan Littlefield
11-24-2010, 09:39 AM

I think it's a great question!! Time and age were invented by humans to bring order to society. There are twenty-four hours in a day, sixty minutes in an hour, sixty seconds in a minute, etc. etc. So, if we slowed time down to make 48 hours in one day, 120 minutes to an hour...heck, I would get a whole lot more done! The only problem is an 8 hour day would become a 16 hour day...

I think it would appear we are aging quicker. Since time is doubled, what is now ten years of age would become half that, meaning we would look ten years older in the new five year span.

Maybe....I don't know.

Sorry if I sound disjointed. Hope this helps. Time to go to sleep soon.

11-24-2010, 09:43 AM
We (and lots of other organisms) have evolved to be attuned to diurnal cycles. Our biological clocks are hard-wired for that. I'm pretty sure psychological experiments have been done to test human clock-time, with rather bad results.

Notably, the people involved in Mars Rover command have had to deal with a Mars day that is 37 minutes longer than the Earth day, meaning that they need to set their sleep/waking hours to drift backwards more than half-an-hour every day. There have been problems adjusting to even that seemingly minor alteration of schedule.

So, no, I don't think we would age any less rapidly.

11-24-2010, 10:06 AM
Do you mean if the earth rotated slower? If so, and if it still took a year for the earth to circle the sun then we wouldn't live as many years, figuring that we have a finite unit of time to live.

That make sense?
However, it could influence our physical selves in ways we can't predict (Even if it was something that had changed over millions of years, and not like a space mission). With more time between sleep, maybe we wouldn't recover from injury as quickly – or with more sleep (which we would also be getting), we could recover faster. Maybe it would add up evenly...? Don't know.

11-24-2010, 10:11 AM
I am not a biologist but...

If Days Were Longer, Would We Age Slower?


11-24-2010, 10:51 AM
No, we would still only live 2.3 1019 oscillations of caesium-133 at 0 K at sea level.

11-24-2010, 11:12 AM
No, human bodies would not age slower if days were longer. Our bodies don't age because of daylight or the length of a day; they're genetically programmed to grow and age at specific rates.

If you want to slow down the aging process, you need to interfere with that genetic programming somehow, or replenish damaged cells, etc.

11-24-2010, 02:37 PM
people would age faster if days were longer in daily terms.

This is because we will still age at the smae rate, but the days are longer, so we would age more in one day.

11-24-2010, 03:36 PM
It's a fascinating question.

I guess it depends on how you view the definition of "aging"

Cosmetically, a lot of aging is damage. The skin ages faster if you expose it to a lot of direct sunlight, for example. If a double length day meant twice as long exposed to the elements followed by twice as long asleep then the amount of exposure to the elements would be the same so presumably damage and cosmetic aging would be the same.

If a person used a 48 hour day to do 8 hours of work, eight hours of self care (cooking healthier meals, going to the gym, skincare etc) and 16 hours of sleep then it would be possible for them to be in better shape, possibly live longer and look healthier.....so looking healthier might be hard to distinguish from looking younger.

8 hours of work followed by 8 hours of drinking and eating junk food may have the opposite effect.

I can't see any reason for growth to slow down. I'd still expect a child to become an adult in the same length of time.....although some hormones have a daily cycle and if that cycle was adapted to a longer time period then that might have an effect on growth and development. We can see people who are either unusually tall or short based on hormone problems so changing hormone cycles could conceivably have an effect.

My instinct is to say that if you moved a group of humans to a planet with a longer day then it would be difficult to adapt and they'd age exactly the same, but if a human civilisation had evolved on a planet with a longer day then there might be enough difference in hormone cycles to make a difference believable.

It might be interesting to research aging in human civilisations near the poles where they certainly have different light/dark cycles.


Plot Device
11-24-2010, 05:04 PM
Will Smith: "Don't you guys ever get any sleep around here? "

Tommy Lee Jones: "We work according to Centaurian time, standard thirty-seven hour day. Give it a few months. You'll get used to it... or you'll have a psychotic episode."

11-24-2010, 05:14 PM
I am not a biologist but...


I was, and I'll take an educated guess and say no. I haven't seen an experiment done on this, so I don't know for sure, but our lifespans are not tied in with our concept of hours/days/years. If we decided to call a year what is now a decade, the maximum human lifespan would be about 12 years, instead of about 120.

Now, if you actually slowed the earth's rotation, I'm still pretty sure that we would age at the same rate. The amount of daylight vs. amount of night don't seem to affect our aging, because those are variable throughout the year anyway, and there are parts of the world that get 24 hours of daylight or night at some points of the year. What would be interesting is if you compared the life expectancy of people from those regions to other regions (while controlling for things like environmental hazards/diet, etc.), and see what happened, because short of actually stepping on the earth's rotational brakes, its probably the closest you'll get to simulating a "longer" day.

I might be able to do better if I had more time to think about it, but it's early and I just woke up.

11-24-2010, 06:35 PM
We would age at the same rate, but we wouldn't live as many days.

11-24-2010, 06:39 PM
If the actual diurnal cycle stayed the same and humans just reclassified 48 hours as a day, no absolute change in lifespan.

If the diurnal cycle were to change so that there were twenty-four hours of sunlight, followed by twenty-four hours of night (with seasonal variations), now that's an interesting question. I think that would have a physiological effect, given humans (and all other Earth creatures) have evolved to deal with much shorter cycles of light and darkness. People might live shorter lives due to disruptions in the sleep cycle, possible increased exposure to solar radiation, and even famines, depending on how the changed cycle affected food crops and animals.

Susan Littlefield
11-24-2010, 07:29 PM
No, we would still only live 2.3 1019 oscillations of caesium-133 at 0 K at sea level.

Did you make that up? :D

Susan Littlefield
11-24-2010, 07:30 PM
We would age at the same rate, but we wouldn't live as many days.

Gee, you said what I was trying to say in half the words....

11-24-2010, 09:23 PM
Did you make that up? :D

Look up the second and how it is defined.

Drachen Jager
11-24-2010, 09:43 PM
It's not an unanswerable question. The answer is NO.

No one knows for sure what the mechanism of ageing is but it's certainly a biological one. People in artificial environments with no night or day don't age differently from people living in the sunlight.

11-24-2010, 09:49 PM
No if 1 day were really two people would only live for half the time. humans biology doesnt relate to human standards of "time". On day light saving time your body doesnt become an hour younger, time is a thing that can change cells in your body dont depend or rely on that time.

11-24-2010, 09:52 PM
I doubt there'd be a correlation. If I were to go way out on a limb, shortening the day might help more than lengthening it. Even if I slept for 16 hours out of 48, that would still mean being awake for 32 hours at a time, for EVERY 48-hour "day." Like many others, I pulled a few all-nighters in college, and my productivity was far from enhanced compared to when I had adequate sleep.

One thing that shortens life is eating too much. The vast majority of people eat too much. People who take in fewer calories (but not TOO fewer, obviously) live longer.

But the idea of living longer has always been a controversial subject, with naysayers asking "why would anyone want to live that long???"

11-24-2010, 09:56 PM
Of course not. Age and life span is not determined by day length, just elapsed time since birth.

Margarita Skies
11-24-2010, 10:07 PM
All right, I consider this question answered, and most of the answers say that we would age at the same rate because our lifespans are not determined by how long the days or the months are. Thank you so much. Have a good day.

Plot Device
11-24-2010, 10:52 PM
Last hurrah from me ....

I heard once that each human being is endowed with only about 2 billion heartbeats over the course of their lifetime. Is that's true, then whether we are operating on a Terran 24-hour day or a Centaurian 48-hour day (it's a 37 hour work day on Centaur, but a 48 hour day-day ;)) then we stil only have 2 billion heart beats, regarless of how ever long it takes for us each to expend our own individual allotment of cardio rhythms.

So there! :)

11-25-2010, 01:32 AM
No, not literally at least. A "day" is a measurement of time, not time itself. So, it's kind of like if you walked forward five feet. If the unit of feet meant something different, then you wouldn't walk five feet anymore, but you would still walk the same distance.

But if the days were longer, how we measure and understand age might change, but we would still age at the same rate.

Though, it would be interesting to think about how longer days might impact people's health, if at all. Many work and school schedules are intended to work out so that people start in the morning, get out in the late afternoon or early evening, and then have a little while to themselves in the evening before going to bed and sleeping 7-9 hours before getting up in the morning and repeating (this is idealized, of course). If days were longer, would people be expected to work or study more hours?

11-25-2010, 01:53 AM
Since life on earth is internally locked into an 24 hour cycle, and expects lighting conditions to coincide with that, you'd get people acting much as before, just that it's now light for two "days" and dark for two. And since the light doesn't follow the sleep cycle, people will generally sleep worse and be less awake, but stretching the cycle to 48 hours is impossible.
Not sure how plants would react to that, some might actually die.

Margarita Skies
11-25-2010, 02:33 AM
All right, I've decided to write this brand new story anyway, but I will set it on a fictitious planet, not on Planet Earth, and the days will be seventy-two earth-days long, and people will age slower than we do. I'm going to change their genetics or something like that to make them age more slowly, because I've never really created a story on a fictitious planet. All my stories, in all genres, have been set on Planet Earth. I'm going to try something new.

11-26-2010, 02:06 AM
the days will be seventy-two earth-days long, and people will age slower than we do.

I hope you meant 72 hours.

If not, remember to set the Monday morning suicide rate at about 10%. I'm not sure that even the "19 earth-hour long" coffee breaks or "3 earth-day long" lunchhours would get me through that week.

On the bright side, I might start managing to write 1000 words a day.