What is the best predictor of lifespan? An expert guide to longevity

September 24, 2025 •

3 min read

According to landmark studies, cardiorespiratory fitness, as measured by VO2 max, is often cited as the strongest physiological predictor of longevity, surpassing other risk factors like smoking. This exploration will reveal what is the best predictor of lifespan and the other critical factors at play.

Quick Summary

The single strongest predictor of lifespan is a nuanced combination of factors, but cardiorespiratory fitness (VO2 max) and strong social connections stand out as exceptionally powerful indicators that are within your control.

Key Points

Cardiorespiratory Fitness (VO2 Max): Often cited as the strongest physiological predictor of a long lifespan, with higher levels significantly correlating to reduced mortality.
Strong Social Connections: Robust social ties act as a powerful non-physiological predictor, providing emotional support and influencing healthy behaviors that reduce stress and mortality risk.
Lifestyle vs. Genetics: For the first 7-8 decades of life, lifestyle factors like diet and exercise are stronger predictors of longevity than genetics, which have a larger role in extreme old age.
Holistic Approach: Longevity is not determined by a single factor, but by a combination of genetics, lifestyle choices, and physiological markers that can be influenced positively.
Actionable Predictors: Unlike unchangeable factors, both VO2 max and social connectedness can be actively improved through consistent exercise and nurturing relationships.
Other Key Markers: Balance, grip strength, and muscle mass are also important predictors, reflecting overall functional capacity and mobility in later life.

Is there a single best predictor?

While there isn't one single predictor of how long you'll live, research indicates that a combination of factors is at play. Among these, cardiorespiratory fitness and social connections are often highlighted as particularly influential and modifiable aspects that impact both healthspan (years lived in good health) and lifespan.

Cardiorespiratory fitness: A key physiological indicator

Cardiorespiratory fitness, often measured by VO2 max, is a strong physiological predictor of longevity. It reflects how efficiently your body uses oxygen during exercise, involving the heart, lungs, and muscles.

The evidence behind VO2 max

Studies, such as a 2018 JAMA study, have shown a significant link between higher VO2 max levels and reduced mortality risk. High VO2 max is also associated with a lower risk of chronic diseases like heart disease and diabetes. Unlike genetic factors, cardiorespiratory fitness can be improved through exercise.

How to improve your VO2 max

Engaging in consistent aerobic exercise, such as running or swimming, and incorporating high-intensity interval training (HIIT) can improve VO2 max. Resistance training also contributes to overall fitness and metabolic health.

Social connections: A powerful non-physiological predictor

Beyond physical fitness, strong social connections are significantly linked to a longer lifespan, sometimes even more so than traditional health risk factors. Social support can help manage stress and encourage healthier behaviors. Research suggests that social isolation can be detrimental to health, comparable to the risks of smoking or obesity.

The influence of genetics and lifestyle

Genetics and lifestyle both contribute to longevity, but lifestyle factors generally have a greater impact for most of a person's life.

Genetics vs. lifestyle


Feature	Genetics	Lifestyle
Overall Influence	Accounts for 20-30% of lifespan variation.	Overwhelmingly the most impactful factor for most people.
Modifiability	Not directly modifiable.	Highly modifiable through daily choices.
How it works	Provides a predisposition for certain conditions or cellular functions.	Directly impacts physiology, disease risk, and overall wellness.
Dominant when...	Becomes more prominent in extreme old age (centenarians).	The primary determinant for the first 7-8 decades of life.

While genetics can play a role, particularly in extreme old age, a healthy lifestyle is the most significant factor for the majority of the population.

Other powerful predictors

Other physical indicators and behaviors are also associated with longevity. These include grip strength, which is linked to overall muscle strength and lower mortality risk; balance, which is important for mobility and reducing fall risk; and muscle mass, crucial for metabolic health and preventing frailty. Additionally, a healthy diet, adequate sleep, and stress management are vital for long-term health and well-being. Minimizing sedentary time is also beneficial.

Practical steps for longevity

To improve your chances of a longer, healthier life, focus on these actionable steps:

Prioritize regular aerobic exercise to enhance cardiorespiratory fitness.
Foster strong social connections by engaging with friends and family and participating in community activities.
Include strength and balance training in your routine to maintain physical function.
Adopt a nutrient-rich diet focusing on whole foods, similar to the Mediterranean diet.
Reduce prolonged sitting and incorporate more movement throughout the day.
Practice stress-reducing techniques like meditation or hobbies.
Aim for 7-9 hours of quality sleep nightly.
Avoid smoking and moderate alcohol intake.

Conclusion: The power of modifiable factors

While no single factor can perfectly predict lifespan, cardiorespiratory fitness and social connections are among the most significant and controllable predictors. By focusing on these and other healthy lifestyle choices, individuals can significantly influence their healthspan and overall longevity. Prioritizing these modifiable factors offers a more effective path to a longer, healthier life than solely focusing on genetics.

For further reading on the powerful impact of cardiorespiratory fitness, explore the scientific statement from the American Heart Association regarding its role as a vital sign. Link to American Heart Association source

Frequently Asked Questions

VO2 max is the maximum amount of oxygen your body can use during maximal exercise. It is a powerful predictor because it reflects the efficiency of your cardiovascular system, which is a major determinant of overall health and resilience to disease. High VO2 max is linked to lower risk of heart disease, diabetes, and other chronic conditions.

Genetics play a role, accounting for roughly 20-30% of lifespan variation, but their influence is far less significant than lifestyle for most of a person's life. While some centenarians may have rare genetic advantages, lifestyle factors are overwhelmingly more impactful for the general population.

Yes, absolutely. Cardiorespiratory fitness is highly modifiable. Consistent aerobic exercise, such as brisk walking, running, or cycling, and high-intensity interval training (HIIT) are effective methods for improving your VO2 max.

Strong social connections combat loneliness and stress, provide emotional support, and can encourage healthier habits. Studies have shown that social isolation can be as detrimental to health as smoking or obesity, underscoring the critical importance of maintaining a robust social network.

Other significant physical predictors include grip strength, balance, leg strength, and muscle mass. Maintaining these through regular training is crucial for mobility, independence, and overall health as you age.

Diet is a cornerstone of longevity. Adopting a healthy dietary pattern, like a plant-based or Mediterranean diet, is linked to a reduced risk of chronic diseases and is a powerful, controllable factor influencing your healthspan and lifespan.

Focus on modifiable lifestyle factors. Increase your physical activity to boost your cardiorespiratory fitness, strengthen your social ties, eat a nutritious diet, get enough sleep, and manage your stress. Consistency with these habits can make a significant difference.

Yes, socioeconomic status, including income, education, and access to healthcare, is linked to longevity. However, focusing on lifestyle factors remains the best strategy for optimizing your personal health, regardless of your socioeconomic background.