The favourable effects of exercise for human and animals has been well established. From ancient Roman and Greek times, the association between exercise and longevity has been understood even though the scientific basis for this association may not have been known. Physical activity in human health is increasingly being “prescribed” for health conditions such as diabetes, osteoporosis and mental health. Exercise is also seen as a key factor in healthy ageing in humans and animals, to counter the onset of “frailty”.

Types of ageing

There are two types of ageing that affect all living beings including our dogs.

• Primary ageing or programmed ageing. This type of ageing occurs at a cellular level. This is a natural process that leads to the eventual degeneration of our cellular structures. This type of ageing is independent of disease or environment. It is inevitable and cannot be reversed. Our maximum lifespan is determined at a genetic level.

• The second type of ageing is referred to as secondary or random ageing. With this type of ageing, disease and environmental factors such as smoking and diet may affect our life expectancy. This type of ageing alters our “programmed” life expectancy. Secondary ageing is thought to be influenced by physical activity.

Frailty in people and dogs

As human lifespan is increasing, particularly in the developed world, the focus of human health has turned to promoting healthy ageing. A concept central to healthy ageing is that of “frailty”.

“Frailty” can be defined as:

• Loss of muscle mass and strength

• Decrease mobility

• Increased weakness

• Low energy expenditure

From a health care perspective, there are two considerations when managing “frailty”. These are:

Firstly, left unaddressed frailty results in poor health outcomes for the sufferer. In humans, it leads to falls, increased rate of hospitalisation and admission to long term care. In the short term, frailty results in loss of independence and eventually, death.

Secondly, if treated the onset of frailty can be delayed. The most important intervention in delaying the onset of frailty is exercise. The best exercise includes a combination of resistance, balance, endurance and coordination training. Exercise protects against the onset of frailty by retaining muscle strength and muscle mass which maintains physical function.

In humans, exercise not only delays the onset of frailty it also has cognitive and social benefits.

Exercise and healthy ageing in humans

Physical benefits of exercise for healthy ageing in humans include:

• Oxygen uptake increases

• Heart rate increases

• Respiratory function increases

• Metabolism responds positively in terms of glucose turnover, energy production and utilisation particularly in the skeletal muscles

Humans who exercise regularly throughout their life, have a more heathy phenotype (gene expression based on interaction with the environment) which slows secondary ageing and reduces the risk of premature death.

Exercise can reverse frailty in mice

A study with mice concluded that four weeks of exercise was sufficient to reverse indicators of frailty in old mice.

The study concluded that exercises improved the following four functional indicators of frailty in a group of old mice.

• grip strength,

• walking speed,

• endurance and

• voluntary activity level

At the beginning of the study, one mouse was defined as “frail” (falling below the threshold on three of the above measures) and one mouse was defined a “mildly frail” (falling below the threshold on two of the measures). After the exercise intervention, no mice were defined as “frail”.

Additionally, the study found significant cellular and physiological changes in response to exercise including improved contractile function in muscles and evidence of hypertrophy (increased muscle mass).

Takeaway messages for dog owners

• The two types of ageing processes apply to dogs too. A lifelong habit of exercise affects second ageing to reduce the risk of premature death and the onset of frailty.

• The definition of frailty in humans can also apply to older dogs. Can you see and feel muscle atrophy (wasting) particularly in your older dog’s hindquarters? Is your dog reluctant to jump onto the furniture or into the car? Is your dog walking more slowly and not wanting to walk for as long?

• Exercise even for older dogs can reverse the onset and progression of frailty. A combined exercise regime of daily walks for endurance and some home exercises for maintaining strength, balance and co-ordination can delay the onset of frailty and maintain your older dog’s quality of life. For ideas on balance, strength and co-ordination exercises you can include in your dog’s daily walk please see https://www.fullstride.com.au/blog/home-exercises-or-a-walk-which-is-better

• Exercise for older dogs, just like humans, can provide social and cognitive benefits. Consider joining a dog walking group or a fun, social training class to keep your dog’s mind as well as their body active.

Please share your tips for promoting healthy ageing in your dogs. Leave a comment here or on the Full Stride Facebook page.

Until next time, enjoy your dogs.

Sources:

Graber, T. G., Ferguson-Stegall, L., Liu, H., & Thompson, L. V. (2014). Voluntary aerobic exercise reverses frailty in old mice. Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences, 70(9), 1045-1058.

Vina, J., Rodriguez‐Mañas, L., Salvador‐Pascual, A., Tarazona‐Santabalbina, F. J., & Gomez‐Cabrera, M. C. (2016). Exercise: the lifelong supplement for healthy ageing and slowing down the onset of frailty. The Journal of physiology, 594(8), 1989-1999.