Healthspan: the healthy prime of life

Lifespan is the amount of time lived. Healthspan is the time lived with vigor and good health. Which do you think is more important?

From birth to physical maturity, there is a rapid increase in function and ability to cope with external stressors in all dogs. Then, as dogs age, health and function begin to decay until death eventually occurs, either directly from a disease or, more often, because humans are forced to make the difficult choice to euthanize a dog because of pain or poor quality of life.  Lifespan is simply the amount of time a dog is alive. Healthspan is the period of life where they are living full, healthy lives, before any major illness or functional decline.

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The impact of increasing healthspan on minimizing the period of poor health preceding death. From McKenzie, BA. Lacroix-Fralish, ML. Chen, F. (2022)The phenotype of aging in the dog: A narrative review. J Amer Vet Med Assoc.

In our view, the goal of maximizing healthspan is equally, if not more important than extending lifespan. Therapies which delay death but do not prolong healthspan might actually reduce overall quality of life by prolonging the period of disability preceding death. Giving dogs and their humans more good quality time together means extending the period of good health, not just the length of life. 

Of course, any therapy which extends healthspan will automatically extend lifespan for many dogs because the number one cause of death is euthanasia. If we improve quality of life and function in older dogs, owners will be able to have more joyful time with their canine companions. 

Currently, veterinary medicine tends to focus on diagnosing, treating, and sometimes preventing individual disease. However, the most important underlying cause for nearly all diseases in adult dogs is aging. The most effective way to extend the healthy period of life is to target the basic mechanisms of aging that reduce our function and ability to cope with stress and/or fight off disease. Targeting these mechanisms could potentially prevent both heart disease and cancer in many dogs, as well as many other diseases we tend to think of as unrelated. 

Healthspan isn’t easy to measure. What is considered “good health” is subjective. The goal of preventing all age-related changes in function and all disease probably isn’t realistic, at least for now. A more practical approach is to consider the number of age-related illnesses that occur, the age at which they happen, and the overall quality of life dogs experience. If we can find treatments that have a clear impact on these measures, we can say we are extending healthspan, and we are likely to also be extending lifespan by improving quality of life and delaying death from illness and euthanasia. As our understanding of aging in dogs improves, and as we develop better tools to measure health and quality of life, we will continue to make progress towards our goals of extending healthspan and giving dogs and their humans more good time together.