If you want to get technical, you’ve been getting older since the day you were born. But a growing body of research has discovered that biological aging doesn’t happen at a steady pace. As a result, there are certain times in your life where your cells may age faster than others.

If it feels like you’ve suddenly developed some post-workout aches that weren’t there a year ago or that you developed grays out of nowhere, you could be going through one of these aging bursts. Naturally, it’s fair to wonder what you can do to stay healthy during this time—and maybe even work against that aging process.

Here’s what the data found about when women age, plus what doctors suggest to slow that process.

The study is just one that found aging happens at set points in life.

For the study, which was published in the journal Nature Aging, researchers analyzed the cells of 108 people between the ages of 25 and 75. They also did a deep dive into participants’ microbiomes, which are microorganisms that play an important role in your health. Most of the participants were tracked for around 1.7 years, although the maximum amount of follow-up was 6.8 years.

After looking at the data, the researchers found that most participants’ molecules and microbiomes aged in bursts. Specifically, they discovered that they went through two periods of faster aging—around age 44 and age 60. “Overall, this research demonstrates that functions and risks of aging-related diseases change non-linearly across the human lifespan,” the researchers wrote in the conclusion.

It’s worth pointing out that this isn’t the only recent study to suggest that aging happens in bursts.

Research published in the journal Cell last year analyzed blood and tissue samples from 76 organ donors who were between the ages of 14 and 68 when they died. Those tissue samples were from a range of bodily systems: cardiovascular, digestive, immune, endocrine, respiratory, skin, and muscular.

Things got a little technical there, but the researchers created a catalogue of proteins from those bodily systems and analyzed how the levels of those proteins changed with age. The thought was that lower levels of the proteins suggest the cells didn’t regenerate as well as they did when the people were younger.

After crunching the data, the researchers found that the biggest aging changes happened between 45 and 55. During that time period, most of the tissues went through major changes, with the most drastic happening in the aorta—the main artery that carries blood away from the heart—as well as the pancreas and spleen.

What’s behind this accelerated aging?

It’s not entirely clear. While research suggests this is a phenomenon that happens, the exact reason for it hasn’t been uncovered yet. Still, there are a few theories.