A New Perspective on Aging: Understanding Intrinsic Capacity
The World Health Organization (WHO) has shifted the global conversation around aging from a disease-centric model to a function-centric one [1.2.5]. Central to this new approach is the concept of intrinsic capacity (IC). Introduced in the 2015 "World Report on Ageing and Health," IC is defined as the composite of all the physical and mental capacities that an individual can draw upon at any point in time [1.6.1, 1.6.3].
This innovative framework encourages a holistic view of an older person's health. Instead of merely treating illnesses, the goal is to develop and maintain the functional ability that enables well-being [1.6.2]. Functional ability itself is determined by the interaction between a person's intrinsic capacity and their environment [1.5.3]. By focusing on and monitoring IC, healthcare providers can detect and address declines early, often before they lead to significant disability or a loss of independence [1.5.6].
The Five Core Domains of Intrinsic Capacity
The WHO has identified five key domains that together constitute intrinsic capacity. These domains are interconnected and provide a comprehensive picture of an individual's health reserves [1.3.6].
- Locomotion: This domain refers to an individual's mobility. It's often assessed through tests like gait speed, the ability to stand up from a chair multiple times (chair-stand test), and balance exercises [1.4.1]. Strong locomotion is fundamental for independence and participating in daily activities.
- Vitality: This domain relates to the body's underlying energy and metabolic health. Key indicators include nutritional status (e.g., assessing for unintentional weight loss or malnutrition), energy levels, and muscle strength, often measured by handgrip strength [1.3.2, 1.4.1].
- Cognition: Cognitive capacity involves mental processes such as memory, attention, orientation (knowing the time and place), and executive function [1.2.7]. Standard assessments like the Mini-Mental State Examination (MMSE) are often used to evaluate this domain [1.4.1].
- Psychological: This domain encompasses mental and emotional well-being. It's typically evaluated by screening for symptoms of depression, anxiety, or a lack of interest in doing things [1.2.7]. Maintaining psychological health is crucial for quality of life and resilience.
- Sensory: Sensory capacity includes vision and hearing. Since declines in these senses can significantly impact communication, mobility, and social engagement, they are considered a foundational component of intrinsic capacity [1.3.6]. Assessment often begins with simple questions or tests like the whisper test [1.3.3].
Intrinsic Capacity vs. Functional Ability: What's the Difference?
It is important to distinguish between intrinsic capacity and functional ability, as they are related but distinct concepts in the WHO's model for healthy aging.
| Feature | Intrinsic Capacity (IC) | Functional Ability (FA) |
|---|---|---|
| Definition | The composite of all physical and mental capacities of an individual [1.2.1]. | The health-related attributes that enable people to do what they value [1.5.3]. |
| Components | An individual's internal reserves (locomotion, vitality, cognition, etc.) [1.3.7]. | The interaction between Intrinsic Capacity and the Environment [1.5.4]. |
| Focus | What the body and mind can do. | What a person actually does in their daily life. |
| Example | A person has the muscle strength and balance to walk 500 meters. | A person walks 500 meters to the grocery store, which is possible due to their IC and a safe, accessible environment (e.g., paved sidewalks). |
The Integrated Care for Older People (ICOPE) Approach
To put the concept of intrinsic capacity into practice, the WHO developed the Integrated Care for Older People (ICOPE) guidelines [1.6.1]. The ICOPE approach provides a practical, person-centered pathway for healthcare workers in community settings to:
- Screen: Use simple tools to screen for declines in any of the five IC domains [1.4.7].
- Assess: Conduct more in-depth assessments if a potential impairment is found.
- Manage: Develop a personalized care plan to reverse, slow, or prevent further declines in capacity.
- Monitor: Regularly follow up on the individual's IC trajectory over time.
This proactive model helps shift healthcare from being reactive to being preventive, with the ultimate goal of maximizing the well-being and independence of older adults. For more detailed information, you can explore the resources on the WHO's website on Ageing.
Why Monitoring Intrinsic Capacity Matters
Focusing on intrinsic capacity offers significant benefits for both individuals and public health systems. By tracking these five domains, clinicians can predict the risk of adverse health outcomes like frailty, falls, and the need for long-term care [1.3.4]. A decline in IC serves as an early warning sign, allowing for timely and targeted interventions.
For older adults, this means a greater opportunity to maintain their independence, engage with their communities, and enjoy a higher quality of life for longer. For health systems, it represents a move toward more efficient, effective, and person-centered care that can help manage the demands of a rapidly aging global population [1.6.1].
Conclusion: A Foundation for Lifelong Health
The concept of intrinsic capacity provides a powerful, positive, and practical framework for understanding and supporting healthy aging. By looking beyond disease and focusing on the sum of an individual's physical and mental strengths, the WHO has created a roadmap for a future where more people can live longer, healthier, and more fulfilling lives. Monitoring and nurturing the five domains of locomotion, vitality, cognition, psychological well-being, and sensory capacity is the key to unlocking this potential.
