The prevalence of hypertension in China has been increasing dramatically [1]. Its prevalence in adults was 27.9% in 2015, an increase of 9.1% compared with the prevalence reported in 2002 by a national survey [2]. Compelling evidence suggests that hypertension contributes greatly to cardiovascular and cerebrovascular diseases [3, 4]. The alarming rise in the prevalence of hypertension and its subsequent complications indicates urgent need to prevent hypertension.

As a modifiable component of lifestyle, regular moderate-intensity physical activity (PA) has been confirmed to be negatively correlated with the occurrence of hypertension [5, 6, 7, 8]. In addition, regular moderate-to-vigorous PA and leisure-time PA are also related to decreased risk of incident hypertension [9]. However, the PA–hypertension link over the course of life has not been well characterized.

To date, most studies have focused on the measurement of PA at a single time, ignoring the dynamic PA changes throughout lifetime [9, 10]. As PA varies over the course of life [11], assessing within-person trajectories of PA over time would better characterize the association between PA and diseases. The existing literature on PA trajectories is mainly focused on cardiovascular disease (CVD), pancreatic cancer, and physical functioning [12, 13, 14, 15], with limited investigations of the relationship between long-term PA trajectories and incident hypertension risk, especially in the Chinese population.

Using repeated measurements of PA taken two to four times during 2004–2011, we aimed to identify the long-term PA trajectories in a national representative sample of adults (18–63 years at baseline and 25–70 years at follow-up), and estimate their associations with incident hypertension using group-based trajectory modeling (GBTM).

In this national prospective study with repeated measurements of PA over the lifetime of participants, we identified five distinct long-term PA trajectory groups in men and two such groups in women. In men, we found that the trajectory group labeled as medium-heavy PA in early adulthood followed by gradual decline was significantly associated with incident hypertension risk in later life.

To date, the research on PA trajectory has focused primarily on CVD and physical functioning; for example, one study showed that a 20-year PA trajectory (moderate increase in PA level from middle age to old age) was associated with a decreased risk of mortality and CVD in later life, with an observed dose-response relationship, and that maintaining even a slight PA was helpful [12]. Another study demonstrated that compared with women in the low PA groups, those in the middle and highest PA groups had more than 5% better physical functioning performance in later life [15]. However, these findings and ours cannot be compared directly owing to the differences in study populations, study design, sample size, methodology, and follow-up time. In addition, the PA calculation in those studies only included sport/exercise and excluded domestic, travel, leisure, and sedentary activities. In contrast, our study incorporated a comprehensive calculation of PA score (MET-minutes/week), and complemented the current evidence of association between PA trajectory and incident hypertension.

Among men, the majority of participants belonged to group 1 (light PA and slight decline), indicating the high prevalence of a light, persistently stable PA trajectory in adulthood. The national representative sample of our study suggests that great effort should be dedicated to promoting PA activities. The Healthy China 2030 platform advocates several strategies to promote the adoption of PA, such as formulating and implementing extensive national fitness campaigns; strengthening the integration of physical and medical pathways (publishing sports and fitness activity guidelines); and formulating and implementing physical health intervention plans for special groups (adolescents, women, the elderly, and disabled people).

Notably, group 4, labeled as medium-heavy PA followed by gradual decline, accounted for 9.2% of the study sample, and was significantly related to decreased risk of incident hypertension. Previous studies have shown that medium-heavy PA in early adulthood is associated with declined hypertension risk [27]. In addition, compared with the reference group, the participants in group 4 were younger; had lower levels of FPG, TG, and UA; had higher levels of HDL-C; had lower fat intake and more protein intake; and included fewer smokers and drinkers. All of these factors were positively correlated to the occurrence of hypertension, with their lower levels contributing to reduced hypertension risk [28]. In this study, we emphasize the importance of maintaining medium-heavy PA in early adulthood, especially for men.

Furthermore, no significant association was observed between the identified trajectory groups and incident hypertension in women. Consistent with our findings, prospective studies also reported non-significant correlation between PA and hypertension risk in women [29, 30]. Both the intensity of PA and the total amount of energy spent are lower in women than in men. Notably, compared with men, woman spend a greater proportion of time engaged in sedentary and light activities and less time engaged in more strenuous (moderate and intense) PA [31, 32]. Furthermore, women’s blood pressure is also influenced by estrogen levels, menstrual cycle, and fertility [33]. Taken together, these findings suggest that women should be the priority target for PA promotion. Our study has important public health implications. Women should be the prioritized target population for physical health interventions. Public health workers should be involved in distributing informative materials related to PA (illustrations, small foldouts, desk calendars, CD-ROMs, etc.) and organizing public awareness activities on PA lectures and health consultations. PA interventions can also be delivered through avenues such as social/familial events to enhance their effectiveness [34]. For example, people could be encouraged to establish an exercise group within the family or sign exercise contracts with each other to complete a certain amount of PA.

To the best of our knowledge, this is the first study to identify the long-term PA trajectories in a representative national sample of Chinese adults and to investigate the effect of PA trajectory on incident hypertension risk. The strengths of our study also include the large sample size, the availability of repeated measures of PA over time, and the use of GBTM. GBTM is a powerful statistical tool that applies limited hybrid modeling and maximum likelihood estimation to determine different PA trajectories [35]. Furthermore, not only occupational but also domestic, travel, leisure, and sedentary activities were included in the calculation of total PA score (MET-minutes/week) in our study.

It should be noted that this study has some limitations. PA was self-reported rather than objectively measured; thus, a certain degree of recall bias cannot be ruled out. In addition, the CHNS only includes the Chinese Han population, so the findings may not be generalizable to other populations. Next, our study is limited by a short follow-up time (average of 5.4 years). At the end of the follow-up period, some young participants may not have developed hypertension. However, the similar results obtained in sensitivity analysis by excluding participants who developed hypertension during the first two years of follow-up are evidence for the reliability of our findings. In addition, the BP was not measured at each interview is also a shortcoming of this study. Finally, due to the absence of the covariate (BMI, energy intake) during follow-up, the covariates at baseline were used in Model 2, 3 and 4.

In conclusion, we identified five distinct long-term PA trajectories in men and two distinct PA trajectories in women. The PA trajectory of medium-heavy PA in early adulthood followed by gradual decline was significantly associated with a decreased risk of hypertension in later life in men. Our study emphasizes the preventive effects of medium-heavy PA in early adulthood against incident hypertension in later life, highlighting that medium-heavy PA should be advocated in early adulthood and should be maintained throughout adulthood.

All authors read and approved the content of the final manuscript. XFC and CJW—conceived the study, coordinated and participated in the data collection, conducted the data analysis and interpretation, developed the first draft, and revised subsequent drafts; LYH, XZ and CS—performed the statistical analysis and drafted the manuscript; HYD, YNM, BYZ and XG—manuscript revision; HPS and GZC—advised on the conception of the study idea, data analysis and interpretation, commented on successive drafts.

The survey protocols, instruments, and the process for obtaining informed consent were approved by the Institutional Review Committees of the University of North Carolina at Chapel Hill, NC, USA, and the China National Institute of Nutrition and Food Safety at the Chinese Center for Disease Control and Prevention, Beijing, China (Approval Number: H-2013-0360). All participants provided written informed consent prior to the surveys.

We would like to acknowledge the CHNS team for the publicly available data.

This study was funded by National Natural Science Foundation of China (81402761); the Foundation Research Project of Jiangsu Province (BK20140361); Suzhou science and technology development project (SS201811); Suzhou Xiangcheng district people’s livelihood science and technology project (XJ201655, XJ201706); Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases (KJS1513). NHC Key Laboratory of Health Economics and Policy Research (Shandong University, Jinan 250012, China). The sponsors of the study had no input in study design, data collection, data analysis, data interpretation, writing of the report, or the decision to submit the paper for publication.

The authors declare no conflict of interest.