We Age in Bursts

In his early 40s, Vinny Minchillo noticed he needed to work harder in the gym just to maintain his usual level of strength. Then, when he turned 60 a few years ago, he noticed a big change in flexibility. 

“I started making noises whenever I bent down to pick something up, or get up or down on the floor,” he said. “And it seemed like these changes occurred in just a week.” 

So when Minchillo read about a new Stanford Medicine study indicating that aging may occur in “bursts” around ages 44 and 60, he felt seen. “It blew me away. That’s exactly what happened to me.”

The study, published in Nature Aging in August 2024, tracked changes in 135,000 molecules and microbes collected from 108 healthy volunteers ages 25 to 75. Researchers observed that participants seemed to undergo dramatic waves of changes at the molecular level, or “aging bursts,” clustered around two distinct times: at age 44 and age 60.

The study assessed thousands of different molecules as well as participants’ microbiomes—the bacteria, viruses and fungi that live inside the body and on the skin. More than 80 percent of the molecules studied showed rapid changes, which are likely to impact health, surging at certain ages. The study’s cohort consisted of people under 75, but a previous study similarly noted spikes of changes in blood proteins occurring around ages 34, 60 and 78.  

“We expected to see changes in the 60s because we know people’s immune systems decline and disease risks go way up at that time,” said Michael Snyder, PhD, professor of genetics and the study’s senior author. “But the burst in the 40s was a bit unexpected.” 

Among participants in their 40s, the Stanford Medicine study noted significant changes in molecules related to caffeine, alcohol and lipid (fat) metabolism, as well as in molecules linked to the cardiovascular system, skin and muscles. For those in their 60s, changes related to carbohydrate and caffeine metabolism, immune regulation, kidney function, and the cardiovascular system, skin and muscle were observed.

At the molecular level, people don’t seem to age gradually and evenly over time. 

Many people experience major life changes or stresses around 44 and 60, which could contribute to the molecular changes, noted Pooja Patel, DrOT, an occupational therapist and elder care consultant. 

“People start retiring around age 60, for example,” she said. “They may not be as active as they were, or they may become more socially isolated. They may start feeling older because they’ve experienced a loss of purpose.”   

Similarly, women typically reach perimenopause in the mid-to-late 40s, and men undergo hormonal changes, including a drop in testosterone levels, around that age. 

However, changes at the molecular level don’t always lead to immediate changes in a person’s health status. 

“Just because something is happening at the biochemical level doesn’t necessarily translate into meaningful life changes,” said Hesan Fernando, PhD, a neuropsychologist at Corewell Health in Grand Rapids, MI. “We see this in individuals who show Alzheimer’s disease pathology in the brain but don’t actually develop Alzheimer’s clinically.” 

More research is needed to make definitive conclusions, including looking at participants’ health status and surveying a larger, more diverse cohort. But the key takeaway remains: people don’t seem to age in gradual, chronological fashion. Instead, they undergo two periods of rapid change. 

Mirrored in Experience 

Medical professionals and others who work with older adults say, anecdotally, that the research reflects their clinical experience. 

“I frequently see patients experience notable shifts in their health around their mid-40s and early 60s,” said Takyrbashev Kubanych, MD, an internal medicine physician. “There may be a sudden drop in stamina, or a new onset of health issues around these ages, despite leading generally healthy lifestyles. And they seem to emerge suddenly rather than developing gradually over time.”

Erin Williams, PhD, and her husband both noticed abrupt changes when their older friends reached the 60-year milestone. 

“They suddenly looked so much older,” said Williams, a psychologist specializing in treating older adults. “Then when it was our turn, it happened to us.”

Williams vividly remembers her 60th birthday a few years ago. She looked in the mirror and fought back tears and feelings of hopelessness. She had worked in health care through the pandemic, and her sleep was fractured. In the previous six years, three close family members had died, and several others struggled with health setbacks. The toll was showing. She had gained weight. Her energy was depleted, and her mind felt foggy.  

That birthday moment spurred Williams to make lifestyle changes: exercising and moving more throughout the day, cutting back on carbs and devoting more time to rest and self-care. She’s feeling more energetic and optimistic now. While she couldn’t stop the aging process, she said, understanding it has helped her cope. 

Managing the Changes

While the reality of aging bursts is sobering, it could also prove reassuring, according to Susan Rebillet, PhD, a psychologist specializing in older adults. She thinks the Stanford Medicine study could help them better understand and manage the changes that come with aging.

“Things can change dramatically as you get older,” she said. “When patients experience big health setbacks, some assume things will go back to ‘normal’ if they just follow the doctor’s orders, or if they exercise more or eat better.” The research, Rebillet said, helps clients understand that some change is inevitable. 

Similarly, Fernando says he often hears from patients who’ve just been diagnosed with a neurodegenerative disease, like Alzheimer’s or Parkinson’s, who ask, “What did I do wrong?” Understanding that changes are happening at the molecular level, and not always within the patient’s realm of control, might reduce the self-blame. 

While good health habits can help slow aging, Fernando added, “We also know that certain genetic factors will override anything we do environmentally or in terms of lifestyle. And some changes are just an inevitable part of life.”  

Preventive Potential 

The Stanford Medicine study doesn’t change the standard recommendations for maintaining good health later in life: eat healthy, exercise regularly, don’t smoke or overindulge in alcohol. But it does point to possibilities for managing patients’ preventative health care more precisely and more proactively. 

Snyder says that might mean increasing exercise to protect the heart, emphasizing strength training to maintain muscle mass or decreasing alcohol consumption in the 40s, as the ability to metabolize alcohol slows. Similarly, while staying hydrated is always important, it becomes even more critical when kidney function tends to decline in the 60s. 

Snyder believes the research points to ways for treating developing issues more proactively. He was also the lead researcher for a 2020 study that determined that people generally age along certain biological pathways in the body: metabolic, immune, hepatic (liver) and nephrotic (kidney). His team dubbed these “ageotypes.” Those who were metabolic ageotypes, for example, might be at a higher risk for diabetes; those with an immune ageotype, on the other hand, might be more prone to immune-related diseases as they age. 

Determining which ageotype applies might allow physicians to tailor more precise and targeted preventive interventions. For example, currently, doctors don’t treat high blood pressure or high cholesterol until levels reach a particular threshold. As aging bursts and ageotypes are better understood, physicians might prescribe medications or other interventions earlier, to prevent systemic, long-term damage. 

As further research is done, more sophisticated interventions are likely to emerge down the road. In the meantime, the Stanford Medicine study’s results are valuable, Fernando said, because they “highlight these potentially vulnerable times in our lives when we need to be extra careful about the decisions that we’re making.”

Minchillo, who’s still in good health and still working, hopes further research might provide clues to help him stay active as long as possible.  

“I need to stay in shape so that I can play on the floor and roughhouse with my grandson,” he said. “I want to be able to do that as long as I can.”