Every week, we’re bringing you a roundup of the latest health and wellness news to hit the wire. This week, we look at new evidence that training for that first marathon makes your arteries younger, we review new findings on what scientists now say are the four different types of aging, and we examine why the “normal” human body temperature has declined.

Your arteries could look four years younger after you run your first marathon

If you’ve been thinking of training for your first marathon, here’s one more reason to do it: New research shows that completing your first marathon may rejuvenate your aorta, leaving this major artery more flexible, healthy and biologically younger than before, according to this report in The New York Times.

Arteries, which carry oxygenated blood from our hearts, begin to stiffen as we reach middle age, driving blood pressure up, rather than expanding and contracting easily to keep blood flow smooth and steady.

Researchers knew that longtime older athletes tend to have relatively elastic arteries. But it was not clear whether sedentary people could achieve the same improvements. So researchers at University College London began studying 200 first-time entrants in the London Marathon—who reported on entry forms that they were new to exercise and to the sport—to find out.

Researchers used health and fitness tests and scans of their aorta designed to measure its flexibility six months before the race. Ultimately, 136 of these men and women completed the race and were given the same tests and scan a week later.

Their aortas were more flexible, shedding the equivalent of about four years in functional terms. The improvements were most significant in older men and those whose finishing times were the slowest.

What’s not clear is whether those benefits will last if they do not continue to race or whether someone needs to go the full 26.2 miles to improve their arteries.

Discovering the “ageotypes” that explain why people age differently

If you have ever wondered why some people seem to age faster or slower than others, a new Stanford University study published in Nature Medicine and covered by NBC News examines what’s going on at the molecular level, with four distinct “ageotypes” or biological systems dictating these changes.

In the study, researchers tracked 43 healthy adults over a two-year-period, analyzing blood and other biological samples to look for molecular changes.

What they found is that people were not only aging at different rates but also in different ways. They found people tended to fall into one of four biological aging pathways or ageotypes— metabolic, immune, liver or kidney.

Metabolic agers, for example, tend to be at higher risk for Type 2 diabetes as they got older. Immune agers generate more inflammation and may be more at risk for immune-related diseases. And liver and kidney ageotypes may be more susceptible to diseases of those organs.

There may be other aging pathways, such as cardio ageotypes that make people more prone to heart attacks, but this research was focused on the four main pathways found in the group. Of these participants, some were found to be aging mainly in certain areas, while others were aging on all four fronts.

The hope is that identifying your primary ageotypes could one day help doctors develop personalized lifestyle and dietary interventions to slow aging in those pathways or influence medical screenings or drug treatments. And if people know their ageotypes or where they have increased risk, they may be more motivated to pursue the healthy lifestyle changes needed to address it.

Human body temperatures are declining

Since it was established by a German physician in 1871, the baseline for normal human body temperature has been set at 98.6 degrees F (37 degrees C). But according to Time Health, researchers at Stanford University now report that the average human temperature has actually dropped, suggesting that doctors need to set a new normal to better establish what constitutes a fever. Analyzing temperature readings from nearly 190,00 people, they found that average temperatures dropped by 0.03 degrees C and 0.29 degrees C each decade for men and women, respectively, over the 150-year span studied. Experts think a taller and heavier population is behind the drop, as well as the heated comfort in which we now live, which requires less of an internal struggle to keep our body warm.

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