6 ms·

From the intro, why this is interesting: > The question of whether mean body temperature is changing over time is not merely a matter of idle curiosity. Human

From the intro, why this is interesting: > The question of whether mean body temperature is changing over time is not merely a matter of idle curiosity. Human body temperature is a crude surrogate for basal metabolic rate which, in turn, has been linked to both longevity (higher metabolic rate, shorter life span) and body size (lower metabolism, greater body mass).

goblin89 7y ago
> Human body temperature is a crude surrogate for basal metabolic rate > higher metabolic rate, shorter life span > lower metabolism, greater body mass In other words, if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! I had some intuition along those lines but thought it’s false, and habitually viewed high metabolic rate as nothing but a “feature” until now. I suppose, then, you might want to be aware of this if you have a young family—get life insurance, if you haven’t already (and I also hope, if this research proves sound, insurers won’t start taking it into account any time soon).
- mjfl 7y ago
  > if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! I think you are making the error of combining the "folk" understanding of high metabolism - that you are skinny, with the scientific understanding of high metabolism, which means you expend a lot of calories every day. It's more likely that you have calorically restricted yourself throughout your life to become skinny, which has longevity benefits, and it's also likely that very fat people burn a lot of calories every day - high metabolism, worse for longevity.
  - AtlasBarfed 7y ago
    My fundamental question on calorie restriction is that women have been doing it for superficial reasons for quite a while, but women's superior life expectancy seems soley due to high risk behavior by men when they are young and middle age. I've never seen anything testing that hypothesis.
    - yojo 7y ago
      There are actuary tables of average life expectancy given a base age. If you are a 70 yo female, you’re expected to live 2 years more than a 70 yo male. https://www.ssa.gov/oact/STATS/table4c6.html https://www.ssa.gov/oact/STATS/table4c6.html It’s possible this difference is a legacy from riskier makes behavior in middle age. I can’t think of a reasonable way to control for this though. Maybe look cross culturally to see if the effect is stable with respect to different male behavior norms?
      - masklinn 7y ago
        > If you are a 70 yo female, you’re expected to live 2 years more than a 70 yo male. The difference is still a year at 86, and doesn't fall to par until supercentenarians.
      - munificent 7y ago
        I wonder how much of that is driven by suicide. Older men commit suicide at much higher rates than older women: https://en.wikipedia.org/wiki/Epidemiology_of_suicide#/media/File:Suicides_by_race_hispanic_gender_and_age_1999-2005.png https://en.wikipedia.org/wiki/Epidemiology_of_suicide#/media...
      - AtlasBarfed 7y ago
        2 years for 40% reduction in daily calories? No fucking thank you. You know what blows away the actuarial tables for life expectancy? Exercise. That makes your life better for longer, much more than starving yourself.
    - masklinn 7y ago
      > I've never seen anything testing that hypothesis. Actuarial tables would tell you. Though there would also be confounding variables e.g. previous "at risk" behaviour could still be in effect.
- AtlasBarfed 7y ago
  But fit people live longer, and high intensity exercise seems to increase DNA repair and antioxidants (the high oxidation of exercise seems to be managed by antioxidant processes kicking into gear, which overcompensate for oxidation versus a sessile person from what I've read... casually)
- masklinn 7y ago
  > In other words, if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! It would also depend whether your skinnyness is metabolic or nutritional (aka do you eat a lot and burn it easily, or eat little / low-calorie stuff).

goblin89 7y ago

> Human body temperature is a crude surrogate for basal metabolic rate > higher metabolic rate, shorter life span > lower metabolism, greater body mass In other words, if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! I had some intuition along those lines but thought it’s false, and habitually viewed high metabolic rate as nothing but a “feature” until now. I suppose, then, you might want to be aware of this if you have a young family—get life insurance, if you haven’t already (and I also hope, if this research proves sound, insurers won’t start taking it into account any time soon).

mjfl 7y ago
> if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! I think you are making the error of combining the "folk" understanding of high metabolism - that you are skinny, with the scientific understanding of high metabolism, which means you expend a lot of calories every day. It's more likely that you have calorically restricted yourself throughout your life to become skinny, which has longevity benefits, and it's also likely that very fat people burn a lot of calories every day - high metabolism, worse for longevity.
- AtlasBarfed 7y ago
  My fundamental question on calorie restriction is that women have been doing it for superficial reasons for quite a while, but women's superior life expectancy seems soley due to high risk behavior by men when they are young and middle age. I've never seen anything testing that hypothesis.
  - yojo 7y ago
    There are actuary tables of average life expectancy given a base age. If you are a 70 yo female, you’re expected to live 2 years more than a 70 yo male. https://www.ssa.gov/oact/STATS/table4c6.html https://www.ssa.gov/oact/STATS/table4c6.html It’s possible this difference is a legacy from riskier makes behavior in middle age. I can’t think of a reasonable way to control for this though. Maybe look cross culturally to see if the effect is stable with respect to different male behavior norms?
    - masklinn 7y ago
      > If you are a 70 yo female, you’re expected to live 2 years more than a 70 yo male. The difference is still a year at 86, and doesn't fall to par until supercentenarians.
    - munificent 7y ago
      I wonder how much of that is driven by suicide. Older men commit suicide at much higher rates than older women: https://en.wikipedia.org/wiki/Epidemiology_of_suicide#/media/File:Suicides_by_race_hispanic_gender_and_age_1999-2005.png https://en.wikipedia.org/wiki/Epidemiology_of_suicide#/media...
    - AtlasBarfed 7y ago
      2 years for 40% reduction in daily calories? No fucking thank you. You know what blows away the actuarial tables for life expectancy? Exercise. That makes your life better for longer, much more than starving yourself.
  - masklinn 7y ago
    > I've never seen anything testing that hypothesis. Actuarial tables would tell you. Though there would also be confounding variables e.g. previous "at risk" behaviour could still be in effect.
AtlasBarfed 7y ago
But fit people live longer, and high intensity exercise seems to increase DNA repair and antioxidants (the high oxidation of exercise seems to be managed by antioxidant processes kicking into gear, which overcompensate for oxidation versus a sessile person from what I've read... casually)
masklinn 7y ago
> In other words, if you are a really, really skinny person (like myself), you would be looking at a statistically shorter lifespan, unless somehow your normal body temp is lower than average or you spot some other sign of decreased basal metabolic rate. Huh! It would also depend whether your skinnyness is metabolic or nutritional (aka do you eat a lot and burn it easily, or eat little / low-calorie stuff).