Researchers studied 611 Dutch adults between 55 and 75 years old to create new fitness standards based on age and sex. They measured how much oxygen people’s bodies could use during exercise on a stationary bike. The study found that fitness naturally declines as we age, but the rate of decline differs between men and women. These new standards help doctors and fitness professionals better understand whether an older adult’s fitness level is normal for their age, which is important for detecting health problems early and tracking improvements from exercise programs.

The Quick Take

  • What they studied: How fit are healthy older adults in the Netherlands, and what fitness levels should we expect for different ages and sexes?
  • Who participated: 611 community-dwelling Dutch adults aged 55 to 75 years old who were generally healthy and living in their own homes
  • Key finding: Fitness (measured by oxygen use during exercise) declines naturally with age, but women lose about 1.3% of their fitness per year while men lose about 2.5% per year. Men and women also have different fitness levels at the same age.
  • What it means for you: If you’re in this age group, these new standards help your doctor understand if your fitness is normal for your age. This is useful for tracking whether exercise programs are working and for catching early signs of health problems. However, these standards apply mainly to Dutch adults and may differ slightly in other populations.

The Research Details

This was a cross-sectional study, which means researchers measured fitness in a large group of people at one point in time, rather than following them over months or years. Participants came to a lab and exercised on a stationary bike while wearing equipment that measured how much oxygen their bodies used. The researchers also measured body composition (how much muscle versus fat each person had) using a special X-ray machine called DEXA. They then created fitness standards by grouping people by age and sex to see what normal fitness looks like for different groups.

The researchers measured four different fitness markers: peak oxygen uptake (the maximum oxygen your body can use), peak work rate (how hard you can pedal), oxygen uptake at the anaerobic threshold (the point where your muscles start working without enough oxygen), and oxygen uptake efficiency slope (how efficiently your body uses oxygen). These measurements give a complete picture of cardiorespiratory fitness from different angles.

The study used advanced statistical methods to create prediction equations—basically formulas that doctors can use to estimate what fitness level is normal for a specific person based on their age, sex, and body composition.

Previous fitness standards for older adults were often incomplete because they didn’t account for differences between men and women, or they excluded people over 70. This study fills that gap by providing detailed standards for people aged 55-75. Having accurate reference values is crucial because it allows doctors to distinguish between normal age-related fitness decline and fitness loss caused by disease or inactivity. This helps with early detection of health problems and allows better tracking of whether exercise interventions are actually working.

This study has several strengths: it included a reasonably large sample size (611 people), used precise measurement methods (DEXA scanning and direct oxygen measurement), and stratified results by both age and sex. However, the study only included Dutch community-dwelling adults, so the results may not apply equally to other populations. The participants were also generally healthy, so these standards may not apply to people with significant health conditions. The cross-sectional design means we see a snapshot in time rather than tracking individuals over years, which limits our ability to understand individual changes.

What the Results Show

All fitness measurements declined with advancing age, which is expected and normal. The decline in peak oxygen uptake (V̇O2peak)—the main measure of fitness—was nearly linear, meaning it decreased at a steady rate. Women lost about 1.3% of their peak oxygen uptake per year, while men lost about 2.5% per year. This means men’s fitness declines faster with age than women’s fitness does.

Significant differences appeared between men and women across all fitness measurements. When comparing people of the same age and body weight, men had higher absolute fitness values than women. However, when fitness was adjusted for lean body mass (muscle mass), the differences were smaller, suggesting that some of the sex difference is explained by men typically having more muscle.

The researchers also found that simpler fitness tests—specifically the anaerobic threshold test and the oxygen uptake efficiency slope—correlated strongly with peak oxygen uptake (correlations of 0.78 and 0.87, respectively). This is important because these simpler tests don’t require maximum effort, making them useful alternatives for people who can’t do a full-effort fitness test.

Peak work rate (how hard people could pedal) also declined with age and showed similar sex differences to oxygen uptake. The oxygen uptake efficiency slope, which measures how efficiently the body uses oxygen at lower exercise intensities, proved to be a reliable alternative measure that correlates well with peak oxygen uptake. The anaerobic threshold—the point where muscles start working without adequate oxygen—also declined with age and showed strong correlation with overall fitness. These secondary findings suggest that doctors have multiple valid options for assessing fitness in older adults.

This study provides the first comprehensive fitness standards specifically for Dutch older adults aged 55-75. Previous reference values either didn’t include people this old, didn’t separate results by sex, or didn’t account for body composition differences. The finding that men’s fitness declines faster than women’s is consistent with some previous research but contradicts other studies, suggesting this may be population-specific. The strong correlation between submaximal fitness tests and peak oxygen uptake aligns with previous research and supports using these easier tests as alternatives.

The study only included Dutch community-dwelling adults, so results may not apply equally to other ethnic groups or countries with different activity patterns. Participants were generally healthy, so these standards don’t apply to people with significant heart or lung disease. The cross-sectional design means we’re comparing different people of different ages rather than following the same people over time, so we can’t be certain about individual aging patterns. The study didn’t include people over 75, so we don’t know if these patterns continue at older ages. Finally, the study measured fitness in a lab setting on a stationary bike, which may not reflect real-world fitness in daily life.

The Bottom Line

If you’re between 55 and 75 years old, these new standards can help your doctor assess whether your fitness is normal for your age. If your fitness is lower than expected, it may indicate a need for more physical activity or investigation of underlying health problems. Regular aerobic exercise (like cycling, walking, or swimming) can help maintain or improve fitness at this age. These standards suggest that maintaining fitness becomes increasingly important as we age, since fitness naturally declines. Confidence level: High for Dutch populations; Moderate for other populations.

These findings are most relevant for adults aged 55-75, their doctors, fitness professionals, and researchers studying aging and fitness. People in this age group should care because these standards help interpret their own fitness test results. Healthcare providers should care because accurate reference values improve their ability to detect health problems early. Fitness professionals should care because these standards help them set realistic goals for older clients. These findings are less relevant for people under 55 or over 75, though the patterns may apply somewhat to those groups.

Fitness changes happen gradually. You won’t notice improvements from a single exercise session, but consistent aerobic exercise over 4-8 weeks typically produces measurable improvements in fitness. Maintaining fitness requires ongoing activity—fitness declines relatively quickly (weeks to months) if you stop exercising. For people starting an exercise program, expect to see noticeable improvements in 8-12 weeks of regular activity.

Want to Apply This Research?

  • Track your aerobic exercise minutes per week (aim for 150 minutes of moderate activity) and note any changes in how hard you feel you’re working at the same exercise intensity. If you have access to fitness testing, track your peak oxygen uptake or work rate annually to monitor whether your fitness is improving, staying stable, or declining.
  • Use the app to set a goal of 150 minutes of moderate aerobic exercise per week (like brisk walking, cycling, or swimming). Break this into manageable sessions (30 minutes, 5 days per week) and log each session. Compare your fitness test results to the age and sex-specific standards provided in this research to understand your current fitness level.
  • Establish a baseline fitness assessment (either through formal testing or estimated from exercise performance), then reassess annually or every 6 months. Track trends over time rather than focusing on single measurements. Note any changes in exercise capacity, such as how far you can walk before getting tired or how hard you need to work to reach a certain heart rate. This long-term tracking helps distinguish normal aging from fitness loss due to inactivity or health problems.

This research provides reference standards for fitness testing in older Dutch adults but should not be used for self-diagnosis. Fitness test results should always be interpreted by qualified healthcare professionals who understand your complete medical history. If you’re considering starting an exercise program or undergoing fitness testing, consult with your doctor first, especially if you have heart disease, lung disease, or other chronic health conditions. These standards apply primarily to Dutch populations and may not be directly applicable to other ethnic or geographic groups. Individual fitness varies widely, and factors beyond age and sex (such as genetics, training history, and health conditions) significantly influence fitness levels.