Profiles of sedentary and non-sedentary young men – a population-based MOPO study

Sedentary behavior has been defined as any waking behavior characterized by an energy expenditure ≤1.5 METs while in a sitting or reclining posture [1]. Excessive sedentary time has been associated with mortality independent of moderate-to-vigorous physical activity (MVPA) [2]. Sedentary behavior has also been linked with adverse health effects such as diabetes, cardiovascular disease and obesity [3]. Even replacing sitting with standing in a work environment may have short-term positive effects on cardio metabolic risk factors [4, 5]. Sedentary behavior defined as television- and video viewing has been associated with body mass index, depression, ethnicity, socioeconomic status, parental education and male gender among adolescents [6]. Despite the known benefits of non-sedentary lifestyle on health, sedentary time in the U.S. has been reported to be 7.7 h per day and adolescents (aged 16–19 years) spend almost 60 % of their waking hours sitting [7]. The increased sedentariness is a global challenge. In most of the western countries less than 40 % of children and youth meet sedentary behavior or screen-time guidelines [8].

The association between gender and sedentary behavior is contradictory. Boys have been reported to be less sedentary and participate more in organized sports than girls [8, 9] but in turn, sedentary time due to television, computer and console games may be problematic issue especially for boys [8, 10, 11]. A generally healthy population of young men may engage in risky behaviors such as physical inactivity and unhealthy diet placing them at risk of health conditions in the future [12]. Because sedentary behavior has been shown to have stability over time and can partially be tracked to adulthood [13], the transition period from adolescence to adulthood may be an important period for monitoring and intervening sedentary behavior patterns.

Various factors are associated with sedentariness, but are not well understood among young adults. Determinants of sedentary behavior among young people are still lacking [14]. In addition, it is not known how sedentary young men differ from their more active counterparts. Thus, our aim was to profile sedentary and non-sedentary young men and to clarify their differences in physical, behavioral, social, and environmental factors. In this study sedentary behavior was defined as any waking behavior in a sitting posture and physical activity considered as overall daily physical activity.

This cross-sectional study is based on a comprehensive population-based study (MOPO), which aims to promote PA and prevent social marginalization among young conscription-aged men [15]. The civic duty or military service is compulsory for male citizens in Finland and conscription is organized every year concerning boys the year they turn 18. Conscription-aged men provide a large, population-based representative sample of Finnish young men.

The non-sedentary men had significantly less body fat, better aerobic fitness and grip strength, less depressive symptoms, and better life satisfaction (Table 1). Their self-rated health and fitness was better, their eating habits were healthier, and they spent less time on the Internet. Furthermore, they reported less binge drinking (p = 0.002) but they used snuff more often (p = 0.002) compared with the sedentary men. Eighty-eight percent (88 %) of the non-sedentary group fulfilled the daily recommendation of 60 min of exercise, compared with 72 % (p < 0.001) of the sedentary group.

In addition, restrictions for PA in sedentary men included more often personal factors such as lack of sport skills or laziness than in non-sedentary men, but improving fitness motivated the non-sedentary men more frequently (Table 3).

In this cross-sectional population-based study of young men, PCA was used for the first time to profile sedentary and non-sedentary young men taking into account a variety of physical, behavioral, social, environmental and health factors. It resulted in profiles that differed somewhat by the sedentary status. The physical performance and mental health of sedentary men were worse than in non-sedentary young men. Those with high leisure sitting time were not necessarily physically inactive and both sedentary and non-sedentary men declared motives to exercise.

Sedentary and PA patterns have been studied especially among children and adolescents, but mainly in respect to dietary patterns [26, 27]. Moreover, previous studies have mostly focused on different actions (i.e., TV viewing, reading, computer usage, homework) within sedentary behavior. Our data had more comprehensive perspective, which included leisure-time sitting, physical performance, other health behaviors as well as both physical and mental health. Thus, these variables enabled to identify groups not been studied before, when resulting in five profiles both for sedentary and non-sedentary group.

Formerly, Gorely et al. [27] have detected three different sedentary clusters “TV viewers”, “computer users”, and “homeworkers,” in addition to “semi-active socializers,” and “actives” among male adolescents. They did not identify a sedentary group, which was exercising, as in our study (i.e. “exercising but sitting”). However, Wang et al. [26] identified five groups of students with unique sedentary and PA patterns, differing by age, screen time and homework time. One of the groups had a sedentary pattern (due to playing computer/video games), but, still, with high PA level. Also in another study, adolescents participating in skating as well as in video gaming had the highest odds of meeting the PA recommendations [28]. Thus, time spent on the internet and engagement in internet games can be associated with both sedentary and non-sedentary lifestyles. Previous studies have also suggested that sedentary behavior and PA do not necessarily displace one another and may coexist. For example the meta-analysis of Pearson et al. [29] found only a minor, inverse association between sedentary behavior and PA among young people. In our study, high levels of PA were found both in sedentary and non-sedentary young men. In the group of “exercising but sitting” high PA, good health together with considerable amounts of sitting (i.e. a health risk) were detected. Thus, our results and previous studies [30] may indicate that adolescents might not recognize their low PA level, or they are not aware of or do not care about its adverse health effects.

Also less sedentary behavior may involve other unhealthy habits such as poor dietary behaviors [31]. Indeed, in the present study unhealthy diet or symptoms of disordered eating were found regardless of sedentary status. On the other hand, our non-sedentary profile “unhealthy diet” (without regular breakfast or use of vegetables) included young men with higher probability of being unemployed, while higher PA has been previously related to being employed [32]. This discrepancy might be somewhat due to the lack of objectively measured PA and sitting time in our study.

None of these other studies measured mental health or wellbeing. In our study, in addition to “gaming”, also “feeling unhappy” – parallel to “symptoms of disordered eating” - were found regardless of sedentary status. Since prolonged sitting [33] and life dissatisfaction have been linked to several adverse health outcomes [18, 19, 34], special attention should be paid to those sedentary young men, who are not feeling well (profile “feeling unhappy”). Also their eating behaviors should be evaluated.

It is not surprising that the non-sedentary young men were in better physical condition, were feeling better, and had healthier lifestyles than the sedentary men. Also previously, leisure sitting time (self-report) has been inversely linked with physical fitness (measured) [35], while sedentary time and low PA has been associated with depressive symptoms and mental problems [36, 37]. Physically active adolescents have also been suggested to spend more time with friends [27]. In our study the lack of friends or lack of possibility to discuss with friends was observed regardless of activity level. However, neither healthy diet nor alcohol intake was related to PA in adolescents [38].

When motives to exercise were studied, the sedentary profile “being unfit with exterior motivation” could be the easiest to activate due to their motives being concrete and outcomes (such as losing weight) easy to measure. Previously, body shape and weight management have been inconsistent in motivating especially teenagers and women [39]. In men, competition, social recognition, and fitness improvement motivate to exercise [40], while having fun has motivated young men. Losing weight can motivate physically inactive people, social factors less educated people [41] and improvement of physical performance adults who are already exercising [41]. In our study, non-sedentary men could be activated through fitness improvement but not through health promotion. Lack of personal factors (interest, skills or knowledge) and laziness were a bigger barrier to exercise among sedentary than non-sedentary men. This is in accordance with the study of Ebben et al. [42], who identified laziness and the lack of motivation as barriers to exercise of physically inactive students.

Our results showed that profiles of sedentary young men differ in socioeconomic situation, physical and mental health, health behavior, PA, and restrictions and motives to exercise. Thus, physical motivation of sedentary young men cannot be based solely on the activity level. Individual unhealthy life habits, and barriers and motivations for exercise have to be considered. In our previous study, we also suggested that more individual and tailored activation with appropriate feedback message tactics is needed [43].

The strength of this study was its population-based design including the entire age cohort of young men and extensive data collection (questionnaire/examination/measurements) with high compliance due to obligatory conscription. The measurements (physical performance/body composition) were carried out under controlled conditions. Using PCA, which combines a large amount of variables into profiles, enabled to reveal new associations and new knowledge. It provides also statistical criteria to the use of sub-scales. Still, interpretation of results provided by PCA is partly subjective, which can be considered as a limitation or a strength of the method.

Nevertheless, a limitation was the lack of objectively measured PA and sedentary time and the lack of data on sedentary time in work activities. Questionnaires have shown limited reliability in respect to PA [44], which is generally overestimated [45] and sedentary time underestimated [44]. Information on daily leisure time sitting was not received from 40.3 % of the participants and the proportion of missing data varied from 0 to 56 % between the variables. Daily PA was based on a simple question with 3 response alternatives. Previous studies have, however, suggested that in addition to validity and reliability, the ease of administration is crucial in population-based studies on other health behaviors besides PA [46]. The nature of sitting was not defined, nor the time spent standing measured, even if the latter is associated with improved health [47, 48]. In this study sedentary time was not split into screen-based and non-screen-based sedentary time since the aim was not to investigate which sedentary patterns are harmful or not. Instead, we wanted to evaluate how overall sedentary lifestyle is built up in young men and factors associated with it.

This study adds to literature on factors underlying sedentary behavior in young men. Sedentary time is a set of multiple behaviors, and on the other hand, non-sedentary lifestyle does not necessarily mean avoiding all possible sedentary actions. In this study we found that there are different profiles in regard to socioeconomic, health, and lifestyle factors among sedentary and non-sedentary young men, even if some factors, i.e. unhealthy habits, gaming, life dissatisfaction, and high self-rated PA, were common and should be recognized both in sedentary and non-sedentary young men. In young men, recognizing individual patterns and underlying factors of sedentary lifestyle and tailoring health promotion for them are essential for effective interventions. These results and profiles can be utilized in planning the future implementation of physical activation of young men. Prospective studies are needed in order to investigate the lifelong trajectories and determinants of sedentary behavior in young men.