Many people hope not only to live longer, but to remain healthy and independent for as much of life as possible. The concept of “compression of morbidity,” first proposed by Stanford professor James F. Fries in 1980, suggests that while the maximum human lifespan may be difficult to extend dramatically, the onset of chronic disease and disability can potentially be delayed. If illness and functional decline occur later in life, most of the lifespan can be spent in good health and independence, with the period of severe frailty compressed into the final years. Recent research continues to explore how lifestyle factors—especially physical activity—may help achieve this goal. Studies conducted in Japan and the United States indicate that meeting recommended physical activity levels, such as engaging in at least 150 minutes of moderate-to-vigorous activity per week or walking approximately 6,000 steps per day, is associated with lower risks of disability and chronic diseases. Although observational studies cannot establish causality, the findings suggest that maintaining regular physical activity may play a meaningful role in promoting healthier aging and reducing the burden of chronic illness later in life.
Moving Disability Further Into the Future: Exercise May Be the “Key”
Many people have imagined what the final stage of life might look like. For some, it may unfold in a hospital bed, with the steady beeping of medical instruments marking the passage of time, as days seem to stretch endlessly. For others, life may continue with the ability to walk, eat, and chat with others, until one day they quietly depart.
In comparison, most people share a simple yet deeply personal wish: not necessarily to live to an extremely old age, but to leave the world with dignity while they can still walk, move, and take care of themselves, rather than spending years confined to a sickbed as life gradually fades away.
As early as 1980, Professor James F. Fries from the Stanford University School of Medicine summarized this simple aspiration into a theory that later became highly influential—the “Compression of Morbidity” hypothesis.
In his view, while the upper limit of human lifespan may be difficult to dramatically extend, the timing of disease onset and functional decline is not necessarily fixed. If chronic diseases, frailty, and disability can be delayed, then most of life can remain active, independent, and dignified. The most difficult period would then be compressed into the final years of life—or perhaps even shorter.
Therefore, rather than merely pursuing “longevity,” humanity may actually be striving for a more ideal life curve: spending most of life able to walk, move, and stay active, and only near the end of life experiencing a relatively brief decline before departing in a relatively healthy state—rather than slowly descending into prolonged frailty and disability.
But how can this vision of “delaying frailty and disability as much as possible” be translated into real life?
Recently, a study published in the Journal of Epidemiology & Community Health (JECH) by researchers from Japan identified exercise as a potential key. The study found that among people younger than 75 years old, consistently achieving the guideline-recommended 150 minutes of moderate-to-vigorous physical activity per week was associated with a significantly lower risk of disability. For individuals aged 75 years and older, walking approximately 6,000 steps per day may already provide potential protective benefits against disability.
DOI: 10.1136/jech-2024-223574
Currently, exercise guidelines issued by both the World Health Organization (WHO) and Japan’s Ministry of Health, Labour and Welfare provide clear recommendations: adults should complete at least 150 minutes of moderate-to-vigorous physical activity each week. Such activities generally include exercises that cause mild breathlessness and an elevated heart rate, such as running, cycling, climbing stairs, brisk walking, or sports like badminton and basketball.
For those who prefer not to measure activity by time, a more intuitive indicator can be used—about 6,000 steps per day, which is also considered a relatively health-friendly level of activity.
However, these recommendations are ultimately based on averages derived from large populations. In real life, people of different ages may not all respond equally to the same activity standards.
In this prospective cohort study, researchers recruited 4,079 community-dwelling residents in Japan. The participants had an average age of 72.7 years, and approximately 56% were women. The follow-up period lasted 58 months.
Participants were first divided into two groups according to whether they met the recommended level of at least 150 minutes of moderate-to-vigorous physical activity per week: those who did not meet the recommendation and those who successfully achieved it.
The results showed that about 12.34% of individuals in the non-compliant group later developed disability, whereas this proportion decreased to 10.17% among those who met the recommended activity level.
In other words, consistently completing at least 150 minutes of moderate-to-vigorous activity per week was associated with an absolute reduction of 2.17% in disability risk.
However, for many older adults, maintaining activities such as running, cycling, or sports may not always be easy. Therefore, researchers also compared participants based on whether they achieved recommended daily step counts.
They found that among those who did not reach the step target, the incidence of disability was 12.00%. Among those who met the step recommendation, the incidence decreased to 9.63%.
This suggests that meeting the recommended step count could reduce the absolute risk of disability by approximately 2.37%.
Interestingly, the reduction in disability risk associated with achieving the step target was slightly greater than that associated with meeting the moderate-to-vigorous exercise recommendation.
This suggests that rather than focusing exclusively on structured exercise programs, simply walking enough each day may already represent a meaningful investment in long-term health.
Staying Active May Reduce the Burden of Chronic Disease
Of course, individuals in their 60s and those in their 80s can differ substantially in terms of physical capacity, lifestyle, and exercise ability. Therefore, researchers further analyzed the participants by age group.
The results showed that different age groups may benefit from different types of physical activity.
Among people younger than 75 years old, meeting the guideline recommendation of at least 150 minutes of moderate-to-vigorous activity per week was associated with a 2.56% reduction in disability risk.
However, for individuals aged 75 years and older, walking around 6,000 steps per day appeared to have greater potential benefits, with a 4.40% reduction in disability risk.
In other words, physical activity may also need to be “age-tailored.” When people are younger and physically capable, they may challenge themselves with higher-intensity activities such as running, swimming, or cycling. As people grow older, maintaining consistent daily walking may become an equally valuable rule for preserving health.
Similar conclusions have also appeared in another study conducted by researchers from the University of Iowa, published in Preventing Chronic Disease.
This study found that compared with individuals who were physically inactive, those who completed at least 150 minutes of moderate-to-vigorous physical activity per week had significantly lower risks of chronic conditions such as obesity, depression, hypertension, diabetes, and heart disease.
DOI:10.5888/pcd22.240149
This retrospective cross-sectional study included 7,261 participants, with a median age of 40 years, of whom approximately 55% were women. All participants completed an Exercise Vital Sign (EVS) screening assessment.
Researchers grouped participants based on their total weekly exercise time. Individuals who reported no exercise at all (0 minutes per week) were categorized as the “inactive group.” Those who exercised between 1 and 149 minutes per week were classified as the “insufficient activity group.” Participants who exercised 150 minutes or more per week were defined as the “active group.”
The analysis showed that the more active people were, the more relaxed their cardiovascular systems tended to be.
Compared with individuals who were inactive or insufficiently active, those in the active group had lower diastolic blood pressure, more stable resting heart rates, lower levels of low-density lipoprotein cholesterol (LDL) and triglycerides, and higher levels of high-density lipoprotein cholesterol (HDL)—often referred to as “good cholesterol.”
Moreover, as physical activity levels increased, the overall burden of disease gradually decreased. Among individuals who did not exercise at all, each person had an average of about 2.2 comorbidities. Among those with insufficient activity, the average was 1.5 comorbidities, while in the active group the number further declined to 1.2 comorbidities.
Specifically, compared with individuals who were inactive or insufficiently active, those in the active group showed significantly lower prevalence of obesity, depression, hypertension, diabetes, and heart disease.
In other words, moving from complete inactivity to meeting recommended activity levels was associated with a clear downward trend in the cumulative burden of chronic disease.
Those who completed at least 150 minutes of moderate-to-vigorous exercise per week were not only physically fitter but also less likely to be burdened by multiple chronic conditions over the long term.
Although life inevitably has an endpoint, the journey leading to that endpoint does not necessarily have to be filled with chronic illness, disability, and prolonged bedridden years.
In many cases, what people truly fear is not death itself, but the long and difficult period before it—when the body gradually weakens, mobility declines, and individuals must constantly struggle with multiple chronic diseases.
This “swamp” of chronic illness and disability may, in fact, be significantly compressed.
Through healthy lifestyle habits—especially maintaining long-term physical activity—many individuals may be able to transform what could have been a decade of prolonged illness into a later stage of life where they can still live independently, enjoy family life, and maintain dignity and quality of life.