Owning a dog may encourage older people to exercise
"NHS should prescribe dogs to keep over-65s fit," the Daily Mail reports.
The headline was prompted by the results of a new study with the rather unsurprising finding that older adults who own dogs walk more than those who don't.
The study included around 80 adults with an average age of 70 from three regions in the UK, half of whom owned dogs. They wore activity monitors for three one-week periods spread over the course of a year.
Dog owners walked around 22 minutes longer each day and were more likely to meet physical activity recommendations of 150 minutes of exercise a week.
It seems plausible that owning a dog directly causes people to go out and walk when they wouldn't otherwise do so.
But you can't rule out the possibility that people who lead more active lifestyles – and so would be active anyway – are more likely to have a dog. Similarly, people with chronic health conditions may be less likely to care for dogs.
The small number of people involved in the study also means we can't provide definite answers around differences in walking times among dog owners – or tell whether this affects health outcomes.
Of course, not everyone wants or can have a dog. That doesn't mean you can't fit exercise into your life – you just need to stick to a routine.
Read more about physical activity guidelines for older adults.
Where did the story come from?
The study was carried out by researchers from several international institutions, including Glasgow Caledonian University and the University of Lincoln in the UK, and State University of New York in the US.
It was funded by the ISAZ/WALTHAM Award, which is administered by the International Society for Anthrozoology (ISAZ). ISAZ is an organisation that provides funding for research into human and animal interaction.
The Mail's coverage is accurate, but the suggestion that the NHS should prescribe dogs to older people oversteps the mark.
The study's authors only suggest that public health campaigns should encourage dog ownership to promote exercise. In any case, it's exercise that's important, and you don't need a dog to do this.
What kind of research was this?
This was a cohort study where a sample of dog owners and non-dog owners, matched on sociodemographic factors, wore activity monitors for three weeks over the course of a year.
The research aimed to see whether dog ownership has a direct effect on physical activity and sedentary behaviour in older adults.
Such a study may well demonstrate that dog ownership has a direct effect on physical activity, but this isn't really that surprising given that the need to walk a dog means a person goes for a walk when they may not have otherwise done so.
What did the research involve?
This study included 43 dog owners and 42 non-dog owners over the age of 65 recruited from Lincolnshire, Derbyshire and Cambridgeshire through advertisements.
Dog owners and non-dog owners were matched by age, gender, ethnicity, and socioeconomic status.
Participants had activity data collected in three one-week periods spread evenly over the course of a year to capture a range of seasons (March to June, July to October, and November to February).
They wore activity monitors and kept diaries reporting walking times and sleep/wake times during the assessment weeks.
Participants also provided data on numerous variables, including:
- their height and weight
- their history of chronic health conditions
- the distance they felt they could walk continuously
- the breed, gender, length of ownership, and extent of personal responsibility for their dog
Researchers, blinded to whether the participants owned a dog or not, assessed walking times and looked at how they adhered with national physical activity recommendations (150 minutes a week of moderate physical activity).
What were the basic results?
Eleven people dropped out of each of the two groups (25% drop out). But compliance with wearing the activity monitors for a full week in each assessment period was very high, at 92%.
Two-thirds of participants were women, with an average age of 70 and an average body mass index (BMI) on the borderline of overweight (25.6kg/m2).
Allowing for variance in dog ownership characteristics, dog owners walked for significantly longer than non-dog owners.
Each day, they walked 2,762 additional steps, and walked 23 minutes longer in total and 21 minutes longer at a moderate walking pace.
But this is a surprisingly high confidence interval, which undermines the validity of this result.
There was no difference in sedentary times or sleep/wake times.
How did the researchers interpret the results?
The researchers concluded that, "The scale of the influence of dog ownership on [physical activity] found in this study indicates that future research regarding [physical activity] in older adults should assess and report dog ownership and/or dog walking status."
This relatively small observational study shows that dog owners over the age of 65 walk more than matched controls who don't own dogs.
This finding is perhaps not surprising, given that dogs need to be walked every day. People without dogs may not have this sort of incentive to get out walking.
So, it could be assumed that the dog is the direct cause of the increased walking time.
But it's also possible that more active people who enjoy spending time outdoors may be more likely to own dogs.
For all we know, the dog owner group may have been more active even if they didn't have dogs.
There are some points to note about this study:
- The study had a fairly small sample and quite a high drop out rate. This means the differences in walking time can't be taken as definite – larger samples of dog walkers and non-dog walkers, or those from different regions, could have given different time differences.
- The big improvement in meeting physical activity recommendations may not be accurate because of the high confidence intervals around the figures.
- If reliable, the roughly 22-minute difference in how much dog owners walked each day may be expected to make a difference to health outcomes, but we can't be certain about that.
- Normal walking/sedentary habits and information about the person's health were self-reported, which may introduce inaccuracies. The research doesn't focus on the health of participants, but it's possible that people with more chronic health conditions could walk less or be less likely to be the main person looking after a dog.
- The sample mainly included women, all the people involved were White British, and all were over the age of 65. This means the results can't easily be generalised to the whole population.
Current public health guidelines recommend taking at least 150 minutes of moderate aerobic activity like cycling or fast walking every week, and strength exercises on two or more days a week.
You don't need to have a dog to be more active – read more about exercise as you get older.
Links To The Headlines
Links To Science
Dall PM, Ellis SLH, Ellis BM, et al. The influence of dog ownership on objective measures of free-living physical activity and sedentary behaviour in community-dwelling older adults: a longitudinal case-controlled study. BMC Public Health. Published online June 9 2017