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Heart age calculators are used worldwide to engage the public in cardiovascular disease (CVD) prevention. Experimental studies with small samples have found mixed effects of these tools, and previous reports of population samples that used web-based heart age tools have not evaluated psychological and behavioral outcomes.
This study aims to report on national users of the Australian heart age calculator and the follow-up of a sample of users.
The heart age calculator was launched in 2019 by the National Heart Foundation of Australia. Heart age results were calculated for all users and recorded for those who signed up for a heart age report and an email follow-up over 10 weeks, after which a survey was conducted. CVD risk factors, heart age results, and psychological and behavioral questions were analyzed using descriptive statistics and chi-square tests. Open responses were thematically coded.
There were 361,044 anonymous users over 5 months, of which 30,279 signed up to receive a heart age report and 1303 completed the survey. There were more women (19,840/30,279, 65.52%), with an average age of 55.67 (SD 11.43) years, and most users knew blood pressure levels (20,279/30,279, 66.97%) but not cholesterol levels (12,267/30,279, 40.51%). The average heart age result was 4.61 (SD 4.71) years older than the current age, including (23,840/30,279, 78.73%) with an older heart age. For the survey, most users recalled their heart age category (892/1303, 68.46%), and many reported lifestyle improvements (diet 821/1303, 63.01% and physical activity 809/1303, 62.09%). People with an older heart age result were more likely to report a doctor visit (538/1055, 51.00%). Participants indicated strong emotional responses to heart age, both positive and negative.
Most Australian users received an older heart age as per international and UK heart age tools. Heart age reports with follow-up over 10 weeks prompted strong emotional responses, high recall rates, and self-reported lifestyle changes and clinical checks for more than half of the survey respondents. These findings are based on a more engaged user sample than previous research, who were more likely to know blood pressure and cholesterol values. Further research is needed to determine which aspects are most effective in initiating and maintaining lifestyle changes. The results confirm high public interest in heart age tools, but additional support is needed to help users understand the results and take appropriate action.
Heart age calculators are increasingly popular worldwide as a way to engage the public in cardiovascular disease (CVD) risk assessment [
Heart age calculators are often used as motivational tools to raise personal awareness about CVD risk factors and prompt follow-up action. Millions of people have used web-based heart age calculators. An international Unilever campaign engaged 2.7 million users from 13 countries in 2009 to 2011 using a Framingham model–based heart age calculator [
With an increasing number of heart age calculators becoming available on the web, it is important to note that the same person can get a very different heart age result depending on which calculator is used [
With so much variability in the way these calculators are set up, heart age is not recommended as a clinical assessment tool for medication decisions [
Existing research on the effect of heart age calculators is divided into small experimental samples that were randomized (which show mixed results overall) [
After conducting an environmental scan of international heart age calculators, the National Heart Foundation of Australia (NHFA) created the Australian version based on Framingham model algorithms. The calculator was developed with funding from an unrestricted and unconditional grant from Amgen, who did not contribute in any way to the development. Some adjustments were made in line with Australian guidelines (eg, ideal levels set at 120 mm Hg for systolic blood pressure and <4 mmol/L for total cholesterol), which resulted in some changes to the weightings for some gender or age groups in the published model. These were tested and discussed with a committee including general practitioners (GPs) and cardiologists to ensure that the calculator would not potentially lead to treatment based on single risk factors. A pop-up message prompted users to see a doctor if the blood pressure or cholesterol level was plausible but considered high risk in accordance with Australian guidelines, for example, “Total cholesterol above 7.5 mmol/L puts you at high risk of having a heart attack or stroke. Please see your doctor as soon as possible about your cholesterol.” Implausible values prompted a different message about the range required, for example, “Please enter a number between 2 and 10.5.” Heart age was calculated once a plausible value was entered. No adjustments were made to account for higher risk populations (eg, Aboriginal and Torres Strait Islander Peoples) because of a lack of clear evidence. The minimum reported heart age was set at <35 years and the maximum at ≥85 years. If blood pressure or cholesterol levels were not known, a population average was used based on the relevant 5-year age group in the National Health Survey data from 2011 to 2012 [
The resulting web-based heart age calculator was intended for people aged 35 to 75 years without existing CVD. The following information was collected: age, sex, family history of premature heart disease, smoking status, height, weight, diabetes status, blood pressure, cholesterol, and whether or not users were taking medication for high blood pressure. Users who did not know their blood pressure or cholesterol were informed that a population average would be used. The result was presented as the user’s heart age and whether it was younger, the same as, or older than their current age. Users were encouraged to provide their email address to obtain a more detailed report and those in the target age group were recommended to see a doctor for a heart health check for absolute risk assessment. The tool is available on the NHFA website [
Example screenshots from heart age calculator (eg, 54 year old male smoker, family history, diabetes and average blood pressure/cholesterol).
Example heart age calculator report (eg, 54 year old male smoker, family history, diabetes, and average blood pressure/cholesterol).
The Australian heart age calculator was launched in February 2019 as part of an NHFA consumer awareness campaign involving mass marketing and media interventions. This
Heart age calculator email journey flowchart.
The calculator could be completed by Australians aged 35-75 years without CVD, in accordance with the target group for CVD risk assessment in Australia.
User data were cleaned to remove duplicates based on internet protocol addresses or email addresses, and users who completed the heart age calculator between February 19 and July 31, 2019, were included in the final data set. CVD risk factors (for all anonymous users), heart age results (for those who requested a report by email), and psychological and behavioral questions (for survey respondents) were linked to the original heart age calculator results. Statistical analysis was performed using IBM SPSS Statistics version 26 (IBM Corp) statistical software package (TB). Descriptive statistics are reported with numbers and percentages for the 3 samples, and exploratory comparisons between age, gender, and heart age category groups in the survey sample were performed using chi-square tests, where a value of
An exemption letter was provided by the University of Sydney Human Research Ethics Committee, as the study involved an analysis of existing anonymized data, originally obtained by the NHFA for internal evaluation purposes.
Overall, data were obtained from 361,044 anonymous heart age calculator users (CVD risk factors only), 30,279 users who provided email addresses to request a report (heart age results) and 1303 survey respondents (psychological and behavioral questions).
Sample flowchart.
Risk factors by heart age calculator user sample.
CVDa risk factors | Anonymous users (n=361,044) | Report requested (n=30,279) | Survey respondents (n=1303) | |||||
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Female | 221,278 (61.29) | 19,840 (65.52) | 867 (66.54) | ||||
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Male | 139,766 (38.71) | 10,439 (34.48) | 436 (33.46) | ||||
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Mean (SD) | 49.37 (11.79) | 55.67 (11.43) | 60.43 (10.15) | ||||
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35-44 | 144,430 (40.00) | 5931 (19.59) | 112 (8.60) | |||
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45-54 | 88,945 (24.63) | 7015 (23.17) | 216 (16.58) | |||
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55-64 | 83,313 (23.08) | 9809 (32.40) | 469 (35.99) | |||
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65-75 | 44,356 (12.29) | 7524 (24.85) | 506 (38.83) | |||
Smoker, n (%) | 35,503 (9.83) | 1957 (6.46) | 39 (2.99) | |||||
Family history of CVD, n (%) | 123,680 (34.26) | 12,844 (42.42) | 587 (45.04) | |||||
Diabetes, n (%) | 20,606 (5.71) | 2290 (7.56) | 89 (6.83) | |||||
Taking BPb medication, n (%) | 64,464 (17.85) | 7950 (26.26) | 413 (31.70) | |||||
Know BP level, n (%) | 178,281 (49.38) | 20,279 (66.97) | 961 (73.75) | |||||
Know cholesterol level, n (%) | 59,013 (16.35) | 12,267 (40.51) | 585 (44.90) |
aCVD: cardiovascular disease.
bBP: blood pressure.
Overall, heart age was on average 4.61 years older than current age, including 78.73% (23,840/30,279) with older heart age and 13.75% (4163/30,279) with younger heart age. Heart age results were significantly different by age group (χ26=1601.1;
Compared with the total sample that requested a report, survey respondents had a slightly higher proportion of people with an older heart age result (1055/1303, 80.97% vs 23,840/30,279, 78.73%) and a slightly lower proportion of people with a younger heart age result (155/1303, 11.90% vs 4163/30,279, 13.75%), but the rates were similar.
In terms of lifestyle behavior, more than half of the survey respondents reported improvements in their diet (821/1303, 63.01%) and physical activity (809/1303, 62.09%), with just under half reporting weight loss (643/1303, 49.35%). Almost one-third of users reported reducing stress (412/1303, 31.62%) and alcohol intake (406/1303, 31.16%). Of those who smoked, 48% (19/39) reported reductions. Some lifestyle change behaviors were reported at higher rates for those with older compared with younger/equal heart age, including diet (680/1055, 64.45% vs 141/248, 56.8%; χ21=5.0;
For outcomes relating to clinical risk assessment, almost half of the users had already seen their GP (621/1303, 47.66%), and one-fourth reported receiving a heart health check (362/1303, 27.78%) in the 10 weeks since receiving their heart age report. Higher proportions had obtained specific clinical tests, with three-fourths of the users checking blood pressure level and more than half obtaining blood tests for cholesterol (737/1303, 56.56%) and diabetes or sugar levels (697/1303, 53.49%). People with an older heart age result were more likely to have visited their doctor (538/1055, 51.00% vs 83/248, 33.4%; χ21=24.7;
Heart age calculator user outcomes after 10 weeks for survey respondents.
Outcomes | All survey respondents (n=1303), n (%) | Older heart age (n=1055), n (%) | Younger or equal heart age (n=248), n (%) | ||||
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Recall of correct heart age category | 892 (68.4) | 735 (69.6) | 157 (63.3) | |||
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Very motivated (a great deal/a lot) | 507 (38.9) | 406 (38.4) | 101 (40.7) | |||
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Very optimistic (a great deal/a lot) | 324 (24.8) | 229 (21.7) | 95 (38.3) | |||
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Very anxious (a great deal/a lot) | 167 (12.8) | 159 (15.0) | 8 (3.2) | |||
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Very worried (a great deal/a lot) | 160 (12.2) | 151 (14.3) | 9 (3.6) | |||
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Spoke to family about familial history | 555 (42.5) | 466 (44.1) | 89 (35.8) | |||
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Found out more information | 787 (60.4) | 669 (63.4) | 118 (47.5) | |||
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Told others about the calculator | 492 (37.7) | 397 (37.6) | 95 (38.3) | |||
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Increased physical activity | 809 (62.0) | 668 (63.3) | 141 (56.8) | |||
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Lost weight | 643 (49.3) | 537 (50.9) | 106 (42.7) | |||
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Improved diet | 821 (63.0) | 680 (64.4) | 141 (56.8) | |||
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Reduced or quit smoking | 19 (48.7) | 19 (48.7) | 0 (0.0) | |||
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Reduced stress | 412 (31.6) | 333 (31.56) | 79 (31.85) | |||
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Limited alcohol intake | 406 (31.1) | 332 (31.4) | 74 (29.8) | |||
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Saw general practitioner | 621 (47.6) | 538 (51.0) | 83 (33.4) | |||
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Had a heart health check up | 362 (27.7) | 314 (29.7) | 48 (19.3) | |||
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Had a blood pressure check | 976 (74.9) | 809 (76.6) | 167 (67.3) | |||
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Had a blood test for cholesterol | 737 (56.5) | 619 (58.6) | 118 (47.5) | |||
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Had a test for diabetes or sugar levels | 697 (53.4) | 587 (55.6) | 110 (44.3) |
The 1077 open response comments were coded and organized into 5 themes from a previous qualitative study on the process of heart age calculator use [
Themes identified in open responses to heart age results.
Themes and subthemes | Example quotes | |
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Perception of lifestyle |
“I'm a bit unsure why as I exercise regularly, don't smoke only drink occasionally, within normal weight range” |
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Information from doctor |
“I had only just had an appointment with my cardiologist and he said my heart is very good” |
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Happy or fine with result |
“I'm on the right track” |
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Surprise at result |
“Surprised and puzzled as to true meaning” |
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Concerned or disappointed |
“I was quite shocked and worried” |
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Defensive at result |
“How is it possible as I had the best possible score therefore everybody must be above” |
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Focus on age or being old |
“It still feels old!” |
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No impression |
“I didn't think that it had any relevance to me” |
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Indicates good health |
“I assumed it meant that my heart was probably in good condition for my age” |
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Indicates health issues |
“I have a higher than average chance of having a heart attack or a stroke” |
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Unsure of meaning |
“Don't really know” |
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Inconsistent with heart age category |
“That I am healthier than average (older heart age result).” “I am unhealthy (younger heart age result)” |
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Interpretation reflects heart age category |
“Heart is older than my age (older heart age result).” “My heart is in better health than it's [SIC] actual age (younger heart age result)” |
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Current or heart age discrepancy |
“79 was extremely scary for a 67 year old (older heart age result).” “It was only one year younger, so it was good, but not great (younger heart age result)” |
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Incorrect or mistrust result |
“The assessment tool was too simplistic to be reliable” |
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Expected result |
“I was aware that this would probably be the case” |
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Risk factors too limited |
“I was annoyed as the questions were quite limited and did not take account lifestyle and medications” |
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Family history or genetics |
“I thought it was elevated because of my family history because I otherwise take good care of my health” |
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Explain result |
“I was not eating properly and exercising enough” |
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No motivation to change |
“I'm on track with my general health” |
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Need to change |
“I thought it meant I had to do some work to get it back to my right age or lower” |
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See a doctor |
“That I needed to see a doctor” |
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Reflection on life |
“An aged heart that hasn't been well taken care of. A wake up call to nuture [ |
This paper is the first report of a national Australian sample of heart age calculator users. It contributes to the broader heart age outcomes literature with a larger sample of population users, who requested a report with follow-up to support behavior change over a 10-week period. In line with other tools used internationally and in the United Kingdom [
The Australian heart age calculator website has been accessed by a large number of people, with 1.3 million users engaged in the first year (internal figures from the NHFA). This paper shows that older people, those more likely to know their risk factors and/or take medication and nonsmokers, were more likely to engage further in health promotion activities via a digital follow-up report. This points to the need for additional strategies to engage people with unknown risk factors and some high-risk groups. Alternative biological age concepts such as
As found in previous experiments comparing heart age to absolute risk [
The launch of the Australian heart age calculator was part of a broader campaign to address barriers to absolute CVD risk assessment, including lobbying for federal government funding of clinical heart health checks. More than half of the survey respondents reported having seen their GP in the 10 weeks since finding out their heart age, and one-fourth of users reported receiving a heart health check. Most users were eligible for a full CVD risk assessment with their GP in line with clinical guidelines targeting those aged 45-74 years. The barriers to engage otherwise healthy adults in preventive health checks are complex, covering all 3 broad determinants of behavior change: capability (eg, lack of knowledge and awareness), opportunity (eg, time and access constraints), and motivation (eg, aversion to preventive medicine) [
Further research is needed to determine whether the behavioral outcomes of heart age calculators can be improved by linking it to additional behavior change strategies known to improve lifestyle change (eg, action planning) [
The main strength of this study is the analysis of a more engaged sample than other national/international heart age user reports (excluding repeat and nonserious users), but the survey respondents are likely biased in terms of motivation and have different characteristics to the broader samples in this study. As there was no randomization, we could not determine causation or efficacy of heart age over other risk communication methods or the length of follow-up required for sustained lifestyle change. The descriptive data available could not be used to determine whether the heart age result itself caused behavior change or whether it simply promoted engagement with further behavior change strategies.
In conclusion, the results confirm high public interest in heart age tools as a way to engage people in the target age for CVD risk assessment and prevention activities, with the potential to prompt clinical risk assessments and lifestyle changes for many users. Supporting the initial heart age result with more detailed reports to explain the results and evidence-based behavior change techniques may improve the effectiveness of these tools.
Follow up survey items.
blood pressure
cardiovascular disease
general practitioner
National Heart Foundation of Australia
This paper was not specifically funded, but C Bonner was supported by a National Health and Medical Research Council/ NHFA fellowship and C Batcup was supported by an NHFA Vanguard Grant for a separate but related study involving a heart age consumer engagement tool led by C Bonner.
None declared.