Scientists from Stanford University and Nanyang University in Singapore claim that humans age at an accelerated pace at two stages in life: at age 44 and then again at age 60.

The new study showed results, published in the journal of Nature Aging, that the researchers found after following 108 study subjects for several years, observing their aging processes and changes in RNA molecules, proteins and microbiome.

They found that human aging does not occur at a constant, gradual manner, but that accelerated aging processes and changes occur in human molecules at age 44 and then again at age 60. "We don't get older at a fixed and gradual pace. There are points in time that are particularly important to our aging and health," said one of the study's leading researchers, an assistant professor of microbiome medicine at Nanyang University in Singapore.

He said that the ability to metabolize caffeine, for example, drops significantly at age 40 and then again at age 60. The metabolism rate of alcohol also decreases significantly at age 40. Michael P. Snyder, chairman of the genetics department at Stanford University, who was also a participant in the new study, said to CNN that "people often suffer from muscle injuries and experience an increase in fat accumulation in their 40s.”

The procedure is related to the metabolism of fats. Sarcopenia (muscle loss) also affects people in their 60s. It's a very significant issue.

The study also found that subjects aged 60 and over were at a higher risk of heart and kidney disease and Type 2 diabetes. The scientists claim in the study that "finding such patterns can help diagnose and prevent diseases."