Why does everything hurt? Research shows our bodies undergo rapid changes at this age

For many people, reaching their mid-40s can be a nuisance, as it can signal that their body isn't working as well as it used to. Injuries seem to happen more frequently. Your muscles may feel weaker.

A new study published Wednesday in the journal Nature Aging suggests what might be behind our decline: Researchers found that the molecules and microbes inside and outside our bodies undergo dramatic changes, first around age 44 and then again as we hit age 60. These changes could make a big difference in our cardiovascular health and immune function.

The survey results are Stanford University scientists who analyzed the blood Additional biological samples from 108 volunteers aged between 25 and 75 years continued to be provided over several years.

“Obviously, aging happens throughout your life, but there are two big periods when things really change,” said Michael Snyder, the study's lead author, a professor of genetics and director of the Center for Genomic Sciences and Personalized Medicine at the Stanford University School of Medicine. For example, “when you reach your 40s, there's a big change in your lipid metabolism, and when you reach your 60s, there's a big change in your carbohydrate metabolism.”

Lipids are fatty substances such as LDL, HDL and triglycerides that serve various functions in the body but can be harmful when they build up in the blood.

The scientists tracked different types of molecules in the samples, including RNA and proteins, as well as the participants' microbiomes.

of Metabolic changes What the researchers found isn't that people in their 40s are burning calories slower, but rather that their bodies are breaking down food differently. Scientists aren't sure exactly how these changes affect health.

In previous research, Resting Energy Expenditure, or Metabolic RateThere was no change from age 20 to 60. The new findings don't contradict that.

Metabolic changes affect how the body responds to alcohol and caffeine, although the health effects are not yet clear (in the case of caffeine, there may be an increased sensitivity).

It's also not yet clear whether these changes are linked to lifestyle or behavioral factors — for example, changes in alcohol metabolism could be the result of people in their mid-40s drinking more alcohol, Snyder said.

For now, Snyder recommends that people in their 40s pay close attention to lipids, especially LDL cholesterol.

“If your blood sugar starts to rise, you might want to consider taking a statin if your doctor recommends it,” he says, adding, “Given that there are changes occurring in molecules that affect muscle and skin, Warm up more before exercising Be careful not to get hurt.”

Until we have a better understanding of what these changes mean, the best way to deal with them is Eat healthy foods Snyder said it's also important to exercise regularly.

Dr. Joseph Koresh, founding director of the Institute for Optimal Aging at the New York University Grossman School of Medicine, likened the new discovery to the invention of the microscope.

“The great thing about this kind of paper is that we can look at molecular changes in great detail,” said Koresh, a professor of medicine at the university, “but it will take time to figure out what each change means and how we can tailor medicines to match them. We know that the origins of many diseases occur in the mid-40s, but the onset of disease can take decades.”

The new study is “an important step forward,” said Dr. Lori Zeltzer, professor of pathology and cell biology at Columbia University's Vagelos College of Medicine. It remains to be seen what the consequences of metabolic changes will be, but “at this point, we have to accept that in your 40s, you metabolize food differently. This is really something new.”

The changes the researchers found could help explain many of the health changes that occur with age, including muscle loss, “because it changes the way your body breaks down food,” Seltzer said.

This article was originally published on NBC News