The present study explored the role of people who had NCDs with respect to high rates of physical inactivity. In this regard, it provided the first findings on the rates at which people who have NCDs met health-oriented PA recommendations in Germany. Our results demonstrated that nearly all subgroups of people who have NCDs met the PA recommendations less frequently than did the general adult population. While it is largely accurate to state that NCDs are associated with insufficient PA, the association should not be over-generalized. Depending on the specific NCD and the type of activity, substantial differences were observed.
The findings support the expert opinions reported in a Delphi consensus study that found a great need for target group-oriented strategies of PA promotion, such as in people having chronic diseases (Gohres & Kolip,
2017). To specify what actions are needed to promote PA among people who have NCDs, it is necessary to more closely examine the differences in prevalence rates by NCDs and type of activity.
Our analyses found that the presence of NCDs was associated with a lower probability of fulfilling PA recommendations. This association was more pronounced for aerobic activity than for muscle strengthening. Insufficient aerobic activity was particularly observed when people reported the presence of obesity, COPD, stroke, diabetes mellitus or depressive symptoms. Furthermore, respondents with cardiovascular diseases as well as back and neck pain also reported a lower prevalence of sufficient aerobic PA. These results are to a large extent comparable with the representative studies already available from the US (Brawner et al.,
2016) and the UK (Barker et al.,
2019), which have focused on the recommendations for aerobic PA. In fact, the order of prevalence estimates was almost identical for the seven NCDs explored both in this study and in the US study (with decreasing prevalence in cancer, osteoarthritis, CHD, diabetes mellitus, obesity, stroke, and COPD); estimates of prevalence were also similar.
Beyond the lower levels of aerobic PA in people with NCDs, four observations were remarkable.
First, people with obesity, diabetes mellitus, or depressive symptoms reported not only the lowest levels of aerobic PA, but also lower rates of fulfilling the recommendations for muscle strengthening. Therefore, these subgroups are at a particularly high risk of inactivity across various activity types. This is important because meeting both recommendations is associated with greater reductions in the risk of mortality than meeting the recommendation for either aerobic activity or muscle strengthening alone (Zhao et al.,
2020).
Second, the number of NCDs present simultaneously was clearly associated with meeting the recommendations for aerobic PA, a finding that is in line with international data (Brawner et al.,
2016). Given the increasing importance of multimorbidities to the German healthcare sector (Puth, Weckbecker, Schmid, & Münster,
2017), PA promotion strategies should focus on people who have multimorbidities.
Third, and somewhat unexpectedly, people who had certain NCDs were more likely to meet the recommendations for muscle strengthening. This is particularly striking in the case of musculoskeletal disorders, for which disease-specific recommendations for muscle strengthening have been established (e.g., Fernandes et al.,
2013).
Fourth, in people who reported osteoarthritis and cancer, the levels of aerobic PA did not differ from the average for Germany’s adult population. This last finding is in line with the results of another recent German study showing that slightly more than half of those diagnosed with cancer reported meeting the recommendations for aerobic activity (Steindorf et al.,
2020).
Our findings can be used as a data source when identifying subgroups particularly vulnerable to physical inactivity. Our analyses of subgroups having different NCDs controlled for sociodemographic characteristics in order to minimize the potential alternative explanations for the differences in PA levels among NCDs. However, differences in PA levels across various NCDs are certainly not attributable per se to the health disorder alone. According to the biopsychosocial health framework of the International Classification of Functioning, Disability, and Health (ICF; WHO,
2001) the effects of health disorders on physical activities greatly depend on various personal and environmental factors regarding the people who have NCDs. That means that individuals deal with health disorders based on the availability of physical and mental resources (e.g., knowledge, physical fitness, motivation regarding PA, and degree of coping with kinesiophobia) in conjunction with social and structural conditions (e.g., social support, availability of adapted PA) (Geidl, Semrau, & Pfeifer,
2014).
Against this background, our findings may encourage further studies seeking to explain the differences in PA behavior among those who have different NCDs, as the cross-sectional study design used provided only limited data on this point. Bearing this in mind, our study’s results indicate that, on average, a certain proportion of insufficient PA in those who have NCDs might be caused by the health disorder itself and its associated symptoms related to body functions. This statement is supported by various reviews and studies of barriers to and facilitators of PA behavior, which have shown that limitations in physical functioning or due to pain caused by diseases like stroke (Jackson, Mercer, & Singer,
2018; Nicholson et al.,
2017), CVD (Stewart et al.,
2013), osteoarthritis (Kanavaki et al.,
2017), back pain (Boutevillain, Dupeyron, Rouch, Richard, & Coudeyre,
2017), or COPD (Thorpe, Johnston, & Kumar,
2012) are significant barriers to sufficient PA. In addition, one could argue that the pronounced physical inactivity of people who have depressive symptoms might be associated with the symptomatology of this mental disorder. Therefore, the general symptoms of depression, including lack of motivation or energy, may be directly related to limitations in physical activities (Glowacki, Duncan, Gainforth, & Faulkner,
2017).
Besides these symptom-related barriers to PA, future research should elaborate more on personal and environmental factors that could further explain the differences among the various NCDs. For example, regarding personal motivation to exercise, a nation-wide survey in German rehabilitation settings found that exercise therapists perceived substantial differences depending on the diseases and health problems they treated (Deprins, Geidl, Streber, Pfeifer, & Sudeck,
2019). In accordance with our findings, exercise therapists reported that patients in oncological rehabilitation programs had the lowest barriers to motivation for PA and the highest enjoyment of PA. In contrast, patients in rehabilitation programs for diabetes mellitus were perceived as having outstandingly high barriers to PA and low levels of concrete ideas regarding incorporating PA into their everyday lives (Deprins et al.,
2019). Further elucidation of such disease-specific differences can enable targeted interventions to promote PA in those having a specific NCD.
In terms of environmental factors, our findings merit further investigation into the role of disease-specific PA recommendations for people who have NCDs. We noted that people who had muscular-skeletal diseases (i.e., osteoarthritis and low back pain) more often reported fulfilling the muscle strengthening recommendations. Regarding promoting PA, we can cautiously conclude that disease-specific PA recommendations may be mirrored in the PA behaviors of certain subpopulations. Therefore, it is interesting to note that, for the first time, current WHO recommendations for health-oriented PA (Bull et al.,
2020), specifically address people with chronic diseases, as Germany’s national PA recommendations already do (Pfeifer & Geidl,
2017). However, further clarification is required regarding, for example, how disease-specific recommendations are related to personal motivation, how they are integrated into medical advice or how they enhance the availability of exercise programs for people with NCDs (e.g., as part of disease-management programs or health-oriented offers by sports organizations). This latter point is likely to vary considerably among the NCDs, which may also contribute to the differences in prevalence rates depending on the NCD and the type of activity. Further clarification of this point will require research that appropriately considers environmental and policy-related determinants of PA at the national, regional, and local levels in Germany (e.g. Bauman et al.,
2012).
Finally, various disease-specific reviews have illustrated that comorbidities represent a barrier to sufficient PA for people with NCDs (e.g., Kanavaki et al.,
2017; Stewart et al.,
2013); this conclusion was generally supported by the present findings regarding multimorbidity. In addition to the higher physical limitations that impair PA in the presence of multiple NCDs (Newsom et al.,
2012; Stewart et al.,
2013), increased attention must be paid to any accompanying depressive symptoms. For example, depressive symptoms have been identified as an additional PA barrier in people with obesity (Adachi-Mejia & Schifferdecker,
2016) and neck pain (Dimitriadis, Kapreli, Strimpakos, & Oldham,
2017). For future research, it would therefore be interesting to further analyze the specific patterns of multimorbidity (e.g., metabolic syndrome, depressive comorbidities) with regard to physical inactivity.
Strengths and limitations
The use of the Scientific Use File of the GEDA-2014/2015-EHIS enabled us to generate information on the PA levels of people with different NCDs in Germany on the basis of a nationally representative dataset. The application of the EHIS-PAQ allowed the explicit consideration of different elements of PA recommendations for both aerobic activities and muscle strengthening. For the indicators used, validation studies revealed that they allow the estimation of compliance with PA recommendations and have sufficient validity for use in surveillance studies and also to inform public policy (Baumeister et al.,
2016; Finger et al.,
2015). Nevertheless, the general limitations for self-report PA measurements (e.g., social desirability, overreporting, and recognition bias) and possible sources of misclassification specific to the questionnaire should be discussed for the EHIS-PAQ.
First, the indicator for health-oriented aerobic activity focuses on meeting the recommendations for at least 150 min of weekly aerobic activity of at least moderate intensity. Thus, an underestimation of the prevalence of achieving aerobic activity recommendations can occur when people complete a minimum of 75 min of vigorous aerobic activity or an equivalent combination of moderate and vigorous activity. Second, for the aerobic PA indicator only, cycling was considered regarding the domain of transportation-related PA. Validation studies of the EHIS-PAQ, which used accelerometer measurements, have pointed to the added value of the combined consideration of leisure-time PA and transportation-related PA (Baumeister et al.,
2016). However, an overestimation of health-enhancing aerobic activity could result, as all cycling is considered to be at least of moderate intensity. In contrast, the prevalence of sufficient aerobic PA could be underestimated, as transportation-related walking with a potentially moderate intensity was not included in the main analyses. The sensitivity analyses have shown, however, that although the prevalence estimates were about 7–15% higher when transportation-related walking was included (Supplementary Table 3); this difference had no significant influence on answering the main questions of our study. Third, the indicator for muscle strengthening estimates the prevalence for fulfilling health-oriented recommendations based only on a weekly frequency. However, PA recommendations usually advise that all major muscle groups should be trained (WHO,
2010). The fact that such information was not assessed is likely to lead to an overestimation of sufficient levels of muscle strengthening.
The limitation of self-reports also applies to the assessment of NCDs. With respect to body mass index-based classifications of obesity, for instance, relevant deviations of self-reported height and weight compared to anthropometric measurements may occur (Nyholm et al.,
2007). Furthermore, no differentiation between type 1 and type 2 diabetes mellitus was possible. Likewise, this study was unable to distinguish between different types of cancer. As a result, we could not account for the fulfillment of PA recommendations that may vary according to the type of cancer (Steindorf et al.,
2020).
Moreover, the response rate of only 26.9% in the GEDA-2014/2015-EHIS has to be considered. It cannot be ruled out that physically active people were more likely to participate in the survey than inactive people, which would lead to a general overestimation of the PA prevalence.