Discussion

Results indicate that knowledge of MVPA guidelines has improved since guidelines were updated in 2011. However, in 2013, still only 18% of adults accurately recounted the recommendations (when only duration was considered). This drops to 11% when only the adults who provided an appropriate description of intensity are considered. This is disappointing as improved knowledge of MVPA guidelines within the adult population would represent an initial step towards positive behaviour change. While knowledge alone is unlikely to stimulate a behaviour change, awareness of the required behaviour is a determinant of behaviour change.24 The PAPM suggests that individuals are unlikely to change their behaviour unless they become aware that their behaviour is not optimal.14 Compared with 2007, adults in 2013 do not appear to be better educated regarding MVPA recommendations.

Mass-media campaigns are currently used to improve the provision of health information to the general public. The release of the most recent guidelines in 2011 was promoted by the Department of Health campaign ‘Change4Life’. Change4Life had a £75 million budget for social marketing to promote five key health behaviours, one of which was PA.25 Early publications from this campaign suggest it achieved a high visibility and recall of its messages within the target populations.25 ,26 While knowledge does appear to be moving in the right direction (at least for duration of MVPA), better results were expected in light of the promotional efforts which have supported the current guidelines. Inconsistency of messaging from Change4Life and other campaigns may create confusion and lead to inaccurate responses. Piggin has previously identified contradictory messages presented by different Change4Life informational materials.27 Indeed, a search of PA campaign messages released since 2011 uncovers various messages which could be perceived as inconsistent. For example, a Change4Life newsletter released in November 2011 stated “Get going every day for 10, 20 or 30 minutes” while an advert released only a few months previously for MacMillan's Move More campaign suggested, “Just a short walk can help…” For World Physical Activity Day 2011, a Coca Cola sponsored advert reads “all this [health benefits] with just 30 minutes of physical activity every day.” Some campaigns have also failed to update their messages in line with the update in the recommendations. The Get A Life, Get Active campaign website homepage has not updated its message since 2009 and still states ‘30 min on most days for adults’. Indeed, 9% of adults from the 2013 sample reported the old guideline (2004–2010) when asked to recall the current guideline (2011). While the aforementioned messages are not necessarily incorrect, campaigns need to become more coherent if the strategy is to improve knowledge of guidelines. Indeed, the unification of the US, UK and global PA guidelines will be undermined if the messages which follow are isolated and random.7–9 The failure of PA campaigns to disseminate consistent messages, both between each other and between various arms within their own campaigns, may have led to misinformation and confusion for many adults.

In addition to the continuing lack of education pertaining to the guidelines, the present research highlights two areas of concern. First, disparities in health knowledge continue to be evident. In both the 2007 and 2013 samples, those with lower education, lower employment status and older adults were less likely to know PA guidelines. The Chief Medical Officers voiced concerns regarding the disproportionately low involvement in PA of disadvantaged groups in the society.8 An improved provision of information and opportunities for these groups to engage in PA was a target of the government-backed campaigns ‘Change4Life’ and ‘HealthyPeople’.28 ,29 Despite these pledges, PA campaigns appear to have been less successful in reaching these groups. The strategies to educate and reach disadvantaged groups within society, especially those with a low education or SES, are urgently required. Second, adults generally consider only the duration component of PA recommendations. While the 2007 HSE sample were asked specifically for the recommended duration of PA, the 2013 survey sample was asked an open question which allowed them to include any aspects of the guidelines of which they were aware of. Despite this, only 11% of adults included an appropriate descriptor of intensity. Even when adults were prompted to provide a descriptor of intensity, only 13% did so. Only 2% provided a physiological parameter which could be practically used to monitor intensity.

In recent years there has been a rise in the number of campaigns promoting lifestyle activities, especially walking, as a proxy for MVPA. While walking is undoubtedly an accessible and appropriate form of PA, the intensity of walking varies greatly within the population. Brisk walking is promoted by many PA campaigns as an example of MVPA, but in actuality, the walking performed by many is less than brisk.30 ,31 While such campaigns may increase the perceived accessibility of PA and cater to adults’ PA preferences,32 they often fail to educate individuals about the necessity for PA to be effortful in order to induce health benefits. It is possible that a lack of knowledge regarding intensity requirements may result in adults engaging in more PA of low intensity but not sufficient MVPA to meet the guidelines. In addition, adults may struggle to see the difference between their own current behaviours and the behaviours being promoted. The PAPM suggests that individuals need to be aware that their actual behaviour is different from the desired behaviour and that this may put their health at risk.14 Awareness of personal risk behaviour is especially important to proceed from precontemplation to contemplating behaviour change. Based on the PAPM, it can be expected that people may only proceed to contemplation when they become aware that they engage in too little PA and/or that their PA is not of a sufficient intensity. With the emergence of alternative strategies to improve health, such as by breaking up sedentary time or increasing light activity, the difference between actual and desired behaviour becomes less obvious. The benefits of engaging in more light activity and of reducing or breaking up sedentary time are evident.33–35 Guidelines regarding sedentary behaviour have already been developed in Canada and Australia and the current UK PA guidelines recommend developing sedentary behaviour guidelines as a priority.8 ,36 ,37 The various discourses surrounding PA and health may cloud directives to the lay population (ie, ‘Is desirable behaviour to be less sedentary, or to be more active, or to do more MVPA?’). While research across the intensity continuum of PA is rapidly increasing, transmitting such knowledge to the general population may require more complex messages but an understanding of how to effectively develop such messages lags behind.

Knowledge of guidelines was low in the present study (ie, only 18% adults knew the duration component of MVPA guidelines); however, this is more than that reported for American adults, where less than 1% knew PA guidelines when surveyed in 2009 (N=4281).20 There are two possible reasons why knowledge was higher in the present study. First, in this study, the MVPA guideline had been consistent for at least 3 years prior to both samples completing their respective surveys. In the American study, only 10 months separated the dissemination of a changed guideline and the completion of the survey. Indeed, 33.3% of American adults selected the old 30 min on 5 days/week guideline relative to 9% in the present study.20 In addition, the American survey employed a closed question with six response options. Two of these were correct according to old guidelines. Prompting from these response options may have triggered more incorrect responses.