Association between joint physical activity and healthy dietary patterns and hypertension in US adults: cross-sectional NHANES study

Hypertension is a global health problem with a leading cause of cardiovascular disease and premature death, which affects about 1 billion adults worldwide [1]. By 2030, 41% of US adults are expected to be diagnosed with hypertension [2]. Hypertension may be caused by a complex combination of risk factors such as a high-sodium and low-potassium diet, sedentariness, smoking, alcoholism, and genetic factors [3, 4]. As hypertension is a chronically progressive disease, some risk factors can be controlled to prevent its development and progression [5].

Previous studies have reported a strong association between diet quality and PA on hypertension [6‐8]. Chronic lack of physical activity (PA) is one of the risk factors for hypertension [9]. Moderate PA may contribute to lower blood pressure and improve cardiovascular health [10, 11]. PA is beneficial in enhancing heart function, inhibiting insulin resistance and inflammation in the body, promoting vasodilation, and lowering blood resistance [12, 13]. Additionally, the reduction in weight, anxiety, and depression that comes with PA can also be helpful to reduce blood pressure [14, 15]. Also, diet is strongly associated with hypertension, and a large number of studies have emphasized the importance of specific dietary patterns (e.g., the DASH diet [Dietary Approaches to Hypertension Control] and the Mediterranean diet) in controlling hypertensio n[16‐18]. Healthy Eating Index 2015(HEI-2015) was developedbased on the Dietary Guidelines for Americans to assess dietary quality. HEI-2015 measures multiple aspects of diet, which provides a comprehensive assessment that can help people to form a healthy habit [19]. It has been proven that strict adherence to HEI-2015 helps aid blood pressure control in hypertensive patients [20].

Previous studies have provided sufficient evidence for the individual impact of PA or healthy dietary patterns in reducing the risk of hypertension. However, there has been no research on the joint effects of PA and healthy dietary patterns on hypertension in a representative sample of adults. To compensate for these limitations, our study used National Health and Nutrition Examination Survey (NHANES) data to explore the association between Joint PA and HEI-2015 and hypertension.

A total of 24,453 participants were enrolled in the main analysis, including 8570 hypertension. The weighted HEI-2015 was 54.2, and the PA level was 3762.36 Met-minutes/week. The mean age was 47.73 years, of which 49.17% were female. According to the lifestyle categories, age, poverty, gender, race/ethnicity, education levels, smoking status, alcohol drinker, marital, hyperlipidemia, diabetes, BMI, and HDL-C have significant differences between groups (P < 0.05) (Table 1).

In this study, we evaluated the joint effect of PA with healthy dietary patterns on hypertension by using the NHANES database. Interestingly, the results showed that the risk of hypertension was lower among participants who followed a healthy dietary pattern and had recommended PA. Our findings provide new evidence for the association between joint healthy dietary patterns and recommended PA and a lower risk of hypertension than those with an unhealthy diet or less than recommended PA. Furthermore, our findings emphasize the combined effect of PA and HE-2105 on hypertension, and that the benefits to reduce the risk of hypertension cannot be achieved by failing to fulfill either of the above two.

PA is known as a modifiable lifestyle change associated with a variety of health outcomes. In a 12-week aerobic exercise trial, it was found that The mean decrease in systolic blood pressure by aerobic exercise was 7.1 mmHg, and the mean decrease in diastolic blood pressure was 5.1 mmHg [37]. However, most studies have focused on the benefits of recreational PA, and little research has been conducted on non-recreational PA. The NHANES assesses participants' PA intensity by collecting information on their work, transport, and recreational activities, which is more consistent with lifestyle [38]. Our study provides additional evidence that PA intensity is strongly associated with hypertension. PA can affect blood pressure through several mechanisms. Studies have shown that PA promotes cardiovascular health, reduces body weight, and improves peripheral arterial resistance [13]. which may explain the association between PA and the prevalence of hypertension [6]. In addition, physical activity may reduce stress-related psychological disorders such as anxiety and depression, further helping to control blood pressure and reduce the incidence of hypertension [14].

A large number of studies conducted in the last decades have emphasized the importance of diet in the risk of hypertension [16‐18, 39]. High sodium intake may contribute to the development of hypertension, while sodium excretion, a surrogate marker of sodium intake, is also highly correlated with blood pressure levels in hypertensive patients [40]. An increase in dietary sodium content leads to an accumulation in sodium retention, which raises the venous tone and central blood volume, thus contributing to the development of hypertension [41]. A plant-based diet consists of high fiber, antioxidants, high potassium, and low saturated fat and sodium [42, 43]. A plant-based diet prevents hypertension and has beneficial effects on blood viscosity, vasodilatation, and reduction of insulin resistance [44]. In addition, with its antioxidant and anti-inflammatory properties and valuable fiber content, it can alter colonies and strains of intestinal flora and improve blood pressure by affecting the renin-angiotensin system and pressure receptors [45]. According to Lea Borgi, long-term fruit use may reduce the risk of developing hypertension [46]. A study conducted in Bangladesh found that higher fruit and vegetable intake was associated with lower annual pulse pressure and systolic blood pressure, while higher meat intake was associated with higher pulse pressure [47].

However, there is a growing emphasis in dietary studies on evaluating overall dietary patterns instead of isolated nutrients or food groups. This approach recognizes that dietary components are interconnected and consumed together[48]. By evaluating dietary patterns, one can overcome the complexity of assessing individual foods or nutrients and their interactions, thus gaining a comprehensive understanding of how overall dietary quality relates to hypertension [49, 50]. Numerous studies have conclusively shown that adopting a healthy diet is strongly correlated with reduced incidence of hypertension and lower mortality rates attributed to hypertension [5, 51, 52]. The HEI-2015 was proposed as a composite measure of dietary quality by the Dietary Guidelines for Americans (DGA), based on evidence-based recommendations from the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS). The HEI 2015 criteria have been shown to be a reliable and accurate measure of nutritional quality for Americans [48], and related studies have also demonstrated that stricter adherence can bring a preventive effect on the development of hypertension [20].

Although recommended PA and healthy diet quality are both independently associated with a reduced risk of hypertension, few studies have examined the combined effects of these lifestyle factors. Interestingly, our study found that the healthy diet and physically active participants alone were negatively associated with hypertension. Previous research has also shown that a DASH diet and exercise significantly reduces daytime ambulatory SBP compared with a DASH diet alone in a hypertensive population [53]. This is consistent with the results of this study. It is important to note that dietary patterns and PA have a strong influence on health and disease risk. Although high levels of PA may help to mitigate the negative effects of certain poor dietary habits, unhealthy eating habits may still increase the risk of developing hypertension in the long run [6, 54]. Therefore, a combination of healthy eating habits and adequate PA is the key to preventing hypertension.

The strengths of this study included a nationally representative design, information on three PA types (strenuous work activity/recreational activity, moderate work activity/recreational activity, and walking/cycling activity), and comprehensive as well as detailed dietary information. Despite this, there are limitations to our study. First, our cross-sectional study design made it difficult to determine causal associations between HEI and PA and hypertension. In the future, prospective observational and intervention studies are needed to explore how PA and dietary patterns prevent hypertension. Second, In NHANES, interviews and questionnaires were used to collect data, and data on diet, bowel, and PA were based on self-reported measurements. This may lead to inaccurate information and recall bias. In addition, PA collected by NHANES is the participant's subjective conscious report of PA, so unconscious PA may be ignored.

Our study shows that recommended PA combined and healthy dietary patterns were negatively associated with the risk of hypertension in a representative sample of U.S. adults. This implies that the combination of recommended physical activity with healthy dietary patterns to prevent hypertension is a practical approach. Therefore, our findings help to identify specific lifestyles that are effective in the prevention of hypertension and provide a useful reference for policymakers to initiate relevant prevention programs and promote them to the public.