Aging in bursts: Why the body speeds up at 40s, 60s, and 80s—and how to slow it down

Science Weekly explores why aging can feel rapid in bursts around the 40s, 60s and beyond, supported by long-term biomarker data. It highlights actionable lifestyle factors—staying active, building muscle, diet quality, sleep and social connections—that may push back the onset and impact of these aging bursts.

Overview

The Guardian Science Weekly episode discusses a non-linear view of aging, challenging the idea of a steady, gradual decline. Hosted by Ian Sample, it centers on a long-running study led by Michael Snyder at Stanford, which tracks aging biomarkers across more than 100 participants aged 25 to 75 over roughly 12.5 years. The team gathers a wide array of data including DNA, blood, urine, RNA, proteins, metabolites and microbiome measurements every three months to build a biochemically detailed picture of age-related changes. The central finding is that aging occurs in rapid bursts rather than as a smooth curve, with major changes in the 40s, a second wave in the 60s, and a third around the 80s. The episode then situates these bursts in the context of skin and muscle, lipid and alcohol/caffeine metabolism, immune function, and muscle mass loss.

"the big bursts of changes in the 40s" - Michael Snyder, director of the Center for Genomics and Personalized Medicine at Stanford University School of Medicine.

What the science shows

The study includes participants aged 25 to 75 and reveals two pronounced aging bursts: one in the 40s and another around the 60s, with a later third around the 80s. The first burst features shifts in skin and muscle mass, altered metabolism of alcohol and caffeine, and changes in lipid metabolism that may drive central fat gain and insulin resistance. The team notes visceral fat around organs increasing during this period, which stresses organs and contributes to cardiometabolic risk. The second burst in the 60s brings major shifts in immune function and sarcopenia, the age-related loss of muscle mass that reduces mobility and health. A third burst around 80 is also observed, tied to reductions in blood stem cell production, potential cancer risk, and further immune challenges.

"aging is not linear" - Michael Snyder.

Why bursts happen

The researchers discuss possible causes, including lifestyle factors that accumulate over time. They hypothesize that years of high activity in adolescence and young adulthood may mask later declines, while midlife pressures such as career and family could contribute to poorer diet and reduced activity, accelerating a burst in the 40s. In the 60s, mitochondrial damage and immune system rejuvenation dynamics may lead to a robust decline in immune function and muscle mass. A separate research thread reports a third spurt in the 80s, alongside declines in hematopoietic (blood-forming) stem cells and a rising risk of cancer. The program emphasizes that while biology imposes limits, much of the pace and severity of aging is modifiable through behavior and environment.

"genetics only accounts for about 16% of your lifespan" - Michael Snyder.

Actionable steps to extend health span

The hosts and researchers highlight practical, achievable strategies to blunt these bursts. Staying physically active and maintaining muscle mass through resistance training is repeatedly described as critical for mobility and health. The episode notes the importance of avoiding ultra-processed foods and excess sugar, which are linked to obesity and diabetes, particularly in Western societies. It also points to dietary patterns associated with immune benefits, such as the Mediterranean or plant-forward diets rich in nuts, vegetables and fish. Adequate sleep (7–8 hours) is emphasized for metabolic and immune health, while social connectivity is cited as an essential factor for maintaining healthspan. The researchers also discuss vitamin D and immune-supportive nutrients, suggesting supplements may be beneficial in some contexts. Finally, the episode notes that some improvements in healthspan can be achieved with modest changes, but sustained, long-term activity and strength training are especially important as people enter their 60s and beyond.

"what's nice about them is they're actionable, meaning you can change your behavior a little bit" - Michael Snyder.

Looking ahead

Although some interventions aim at extending life, Snyder emphasizes the real goal: living longer, healthier years. He discusses ambitious ideas such as preserving stem cell activity and targeting senescent cells, alongside lifestyle strategies. He cautions that while there is interest in dramatic anti-aging technologies, the more immediate path is through everyday health behaviors that influence energy production, immune resilience and muscle maintenance across the lifespan. The episode closes with a call to empower people to pursue healthier aging trajectories through informed choices and ongoing science.

"we want people to live long, healthy lives, and then, to be honest, and just pass away after having a healthy life" - Michael Snyder.