Skip to main content
Advertisement
Browse Subject Areas
?

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here.

  • Loading metrics

Joint association between physical exercise, caffeine intake, and biological ageing: A cross-sectional analysis of population-based study

  • Guang Chen ,

    Contributed equally to this work with: Guang Chen, Shichen Zhou

    Roles Conceptualization, Data curation, Formal analysis, Methodology, Writing – original draft, Writing – review & editing

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • Shichen Zhou ,

    Contributed equally to this work with: Guang Chen, Shichen Zhou

    Roles Data curation

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • Yunqing Xun,

    Roles Data curation

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • Tung Leong Fong,

    Roles Data curation

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • Guoyi Tang,

    Roles Data curation

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • Jingyi Wang,

    Roles Data curation

    Affiliation Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China

  • Hongzheng Li,

    Roles Formal analysis

    Affiliation Guang’anmen hospital, China Academy of Chinese Medical Sciences, Beijing, China

  • Xiangjun Yin,

    Roles Formal analysis

    Affiliation School of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, China

  • Jialiang Gao,

    Roles Formal analysis

    Affiliation Guang’anmen hospital, China Academy of Chinese Medical Sciences, Beijing, China

  • Guanghui Zhu,

    Roles Methodology

    Affiliation Guang’anmen hospital, China Academy of Chinese Medical Sciences, Beijing, China

  • Ying Wu,

    Roles Supervision

    Affiliation Harvard Law School, Harvard University, Cambridge, Massachusetts, United States of America

  • Jinlin Li,

    Roles Supervision

    Affiliation PBC School of Finance, Tsinghua University, Beijing, China

  • Ya Xuan Sun,

    Roles Methodology

    Affiliation T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America

  • Yige Li,

    Roles Methodology

    Affiliation Department of Health Care Policy, Harvard Medical School, Harvard University, Boston, Massachusetts, United States of America

  • Jiayan Zhou,

    Roles Methodology

    Affiliation School of Medicine, Stanford University, Stanford, California, United States of America.

  •  [ ... ],
  • Yibin Feng

    Roles Funding acquisition

    yfeng@hku.hk

    Affiliation School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR of China

  • [ view all ]
  • [ view less ]

Abstract

Background

Ageing is a significant risk factor for age-related diseases, accounting for 51% of global total disease burden. As thus, promoting healthy ageing is crucial. Although several potential anti-ageing drugs show promise, none have been approved for anti-ageing purpose. The World Health Organization (WHO) recommends physical exercise exceeding 600 metabolic equivalent of task (MET) minutes per week for adults. However, whether physical exercise positively impacts healthy biological ageing remains unclear.

Objective

This study aimed to investigate the joint correlation between MET level, caffeine consumption, and biological ageing.

Methods

We analyzed data from seven survey cycles (2007–2020) of the National Health and Nutrition Examination Survey (NHANES), involving 23,739 participants. Physical activity levels were measured in MET minutes per week, and biological ageing was assessed using both the PhenoAge and ENABL Age algorithms. Generalized linear regression for survey data was employed to test correlations, adjusting for confounding factors. A cubic spline model was used to detect non-linear relationships. Pre-specified subgroup analyses explored effect modifications, while predefined sensitivity analyses confirmed the robustness of the results.

Results

Each 100-MET increase in weekly physical exercise was associated with a 0.2-year delay in biological ageing (p < 0.001 for both PhenoAge and ENABL Age). Individuals with less than 600 MET minutes of weekly exercise had a higher risk of accelerated ageing compared to those exceeding 600 MET minutes (mean difference [MD]: 2.2 PhenoAge years, 95% CI [1.5–2.8], p < 0.001; MD: 2.1 ENABL Age years, 95% CI [1.1–3.1], p < 0.001). A L-shaped association was observed, with diminishing benefits of delayed ageing beyond 292 MET minutes for PhenoAge and 259 MET minutes for ENABL Age. Daily caffeine intake did not modify the correlation between MET levels and biological ageing (p for interaction > 0.05). Stronger effects were observed in non-Hispanic Black individuals, those with obesity, and low-income populations, but no benefit was found in cancer patients.

Conclusions

Our findings highlight a positive correlation between higher levels of weekly physical exercise and delayed biological ageing. However, the benefits plateau beyond specific MET thresholds. Caffeine intake does not influence this relationship. These results underscore the importance of promoting physical exercise at appropriate MET levels as a strategy for healthy ageing management in the general population.

Introduction

Ageing is defined as the progressive decline in biological function over time [1] and is characterized by 12 key hallmarks, organized into three overarching aspects: (1) causes of damage (genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, and disabled macroautophagy), (2) responses to damage (deregulated nutrient sensing, mitochondrial dysfunction, and cellular senescence), and (3) culprits of phenotype (stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis) [2]. An individual’s ageing status can be quantified and estimated using predictive biomarkers identified through phenotype and omics studies [3,4]. These biomarkers are incorporated into algorithms such as DNAmAge [5], GlycanAge [6], GrimAge [7], PhenoAge [8], and ENABL Age [9], enabling the evaluation of longevity interventions [10]. Ageing research is both crucial and unique because ageing is a primary risk factor for a wide range of age-related diseases, including various cancers, neurodegenerative disorders, cardiovascular diseases, and metabolic conditions such as diabetes [11]. Notably, an updated Global Burden of Disease (GBD) study revealed that these age-related diseases account for 51.3% (95% CI: 48.5–53.9) of the global disease burden [12]. Consequently, promoting healthy ageing is essential for enhancing both lifespan and quality of life.

Currently, no anti-ageing intervention has been proven to be both effective and safe. Risk factors including overweight [13], a high dietary inflammation index [14], and negative emotion such as anger [15] have been associated with accelerated ageing, while protective factors including regular sleep patterns are linked to delayed ageing [16]. However, no causal relationship between these factors and ageing has been conclusively established. Beyond these physical, emotional, and behavioral factors, researchers globally are actively exploring pharmacological interventions to mitigate ageing. The hallmarks of ageing are defined by the principle that experimental augmentation of these hallmarks accelerates biological ageing, whereas therapeutic interventions targeting them can decelerate, halt, or even reverse the ageing process [2,11,1316]. Eight pharmacological compounds targeting these ageing hallmarks have been investigated in human trials, including metformin, oxidized Nicotinamide Adenine Dinucleotide (NAD+) precursors, Target of Rapamycin Complex 1 (TORC1) inhibitors, Glucagon-Like Peptide-1 (GLP-1) receptor agonists, probiotics, senolytics, spermidine, and anti-inflammatories [17]. Additionally, vaccines are being explored for their potential to combat ageing and age-related diseases [18]. Despite these advancements, no anti-ageing drug has yet received approval from the U.S. Food and Drug Administration (FDA), and all potential candidates remain controversial due to uncertainties regarding their efficacy and safety in humans [19].

The World Health Organization (WHO) strongly recommends that adults engage in at least 600 metabolic equivalent of task (MET) minutes per week, which translates to 75 minutes of vigorous-intensity or 150 minutes of moderate-intensity physical activity weekly [20]. Similarly, the Physical Activity Guidelines for Americans advocate for a minimum of 600 MET minutes per week, supplemented by muscle-strengthening activities on two or more days per week [21]. Despite these recommendations, the relationship between MET levels in physical exercise and healthy ageing remains unclear, particularly in subpopulations with chronic diseases such as cancer survivors. While higher physical activity levels following cancer diagnosis and treatment have been associated with reduced mortality in breast, prostate, gynecological, and colorectal cancers, this correlation is less certain in lung cancer patients [22]. Additionally, many cancer survivors face challenges in performing and adhering to regular physical exercise due to fluctuating cancer-related symptoms and demanding treatment schedules [23].

In parallel with physical activity, caffeine consumption has gained attention for its potential influence on biological ageing. Research indicates that caffeine intake is associated with improved cognitive performance, a recognized phenotype of biological ageing [24]. Additionally, a randomized, double-blind, crossover, placebo-controlled study among cyclists demonstrated that caffeine enhances exercise performance and provides cardio-protective effects during intense physical activity [25]. Despite these promising findings, the combined impact of exercise and caffeine consumption on biological ageing remains underexplored. Therefore, our study aimed to investigate the joint correlation between MET levels, caffeine consumption, and biological ageing.

Materials and methods

Study design and population

The National Health and Nutrition Examination Survey (NHANES), a nationwide cross-sectional survey, investigates the nutrition and health conditions in the US population (https://www.cdc.gov/nchs/nhanes/index.htm). This study was approved by the national center for health statistics ethics review board (Approval number: #2018-01). All participants provided the written consent before the enrollment, and the written consent can be found on the NHANES website (https://wwwn.cdc.gov/nchs/nhanes/continuousnhanes/documents.aspx?BeginYear=2017). The information collected in this survey encompassed demographics, socioeconomic status, lifestyle and health questionnaires, and bio-specimen data. In this study, we included seven NHANES cycles (2007–2008, 2009–2010, 2011–2012, 2013–2014, 2015–2016, 2017–2018, 2019–2020). Participants were excluded if they were 18 years of age or younger, pregnant, or had missing data on physical exercise.

Measurement of exposure

The participant’s weekly physical exercise and activity amount was measured by MET in the NHANES database. MET per week was calculated by vigorous work and recreational activity minutes per week, moderate work and recreational activity minutes per week, and walk or bicycle minutes per week. Typically, 600 MET is equivalent to 75 minutes of vigorous intensity physical activity or 150 minutes of moderate physical activity per week [20]. Physical exercise was categorized into two classes based on the WHO recommendation for adults: adequate level of physical exercise (MET ≥ 600 per week) and inadequate level of physical exercise (MET < 600 per week) [20]. Daily caffeine consumption primarily originates from coffee, tea, cola drinks, and chocolate. Participants’ caffeine consumption was quantified in urine (umol/L) using high-performance liquid chromatography-electrospray ionization-tandem quadrupole mass spectrometry in the HNANES database [24].

Ascertainment of outcomes

Biological ageing was calculated for both PhenoAge [8] and ENABL Age [9] for all participants surveyed in NHANES. PhenoAge was calculated based on chronological age and clinical biomarkers which correspond to estimated mortality risk, including concentration of albumin, glucose, C-reactive protein (CRP), alkaline phosphatase, creatinine, red blood cell distribution width, mean cell volume, lymphocyte percent, and white blood cell count. ENABL Age, also incorporating clinical biomarkers, can distinguish unhealthy ageing from the healthy ones, and predict 5-year mortality with the power of an area under the receiver operating characteristic (ROC) curve of 0.89 and 0.91 for 10-year mortality on the NHANES dataset.

Extraction of confounding factors

The factors that were unbalanced across exercise exposure groups and were shown to be correlated with ageing, were defined as confounding factors in this study [26]. In our study, confounding factors include sex (female/male), race (Non-Hispanic Black/Non-Hispanic White/Other Hispanic/ Mexican American/other race including multi-racial), body mass index (BMI) (≤25 kg/m2 as normal, > 25 to < 30 kg/m2 as overweight, ≥ 30 kg/m2 as obesity), marital status (married/divorced/widowed/separated/never married/living with partner), income (assessed by income poverty ratio), sleep disorder (with/without), smoking status (never or ever), alcohol intake (never or ever), and history of cancer diagnosis (never or ever) [26].

Statistical analysis

Baseline characteristics were calculated and listed across groups with MET < 600 and MET ≥ 600 using Python package tableone. Continuous variables were described in mean (SD) or median (IQR); categorical variables were shown as absolute numbers along with percentages. According to the statistical guidance on the NHANES website, modeling weights were added based on sampling design and weights for each survey cycle in our analysis model svyglm in R. All regression analyses were controlled for confounding factors by adding covariates in the multivariate regression models.

We used generalized linear regression model to test the correlation between total MET per week and biological ageing, between MET category (< 600 or ≥ 600) and biological ageing, controlled for confounding factors including race, sex, income, marital status, BMI, sleep disorder, alcohol intake, smoking, and history of cancer, while incorporating the NHANES weights across each survey cycle.

Non-linear correlation was explored by the cubic spline models between total MET per week and biological ageing. The non-linear P value indicates whether there was statistically non-linear association, and the cut-off point was detected if non-linear correlation existed.

Subgroup analysis was conducted to figure out effect modifiers, where we stratified the regression models by sex (male vs. female), race (Non-Hispanic Black vs. Non-Hispanic White vs. Other Hispanic vs. Mexican American vs. other race), BMI (≤25 vs. > 25 to < 30 vs. ≥ 30 kg/m2), family income poverty ratio (1 vs. 1–4 vs. > 4), smoking status (current smoker vs. former smoker vs. nonsmoker), and history of cancer diagnosis (with vs. without) [26].

The following sensitivity analyses were also conducted to test the robustness of the regression results. First, we excluded participants with cancer because cancer is shown to affect the exercise ability and also negatively affect the healthy ageing. Second, we did the sensitivity analyses to examine the association between biological ageing and weekly vigorous intensity physical activity. Third, we did the sensitivity analyses to examine the association between biological ageing and daily vigorous intensity and moderate intensity physical activity.

We used R package rcssci for cubic spline models and verified the results by porstrcspline in Stata package. All other analysis and plot were conducted using R, with statistical significance set at a p-value of 0.05.

Results

Baseline characteristics and descriptive statistics

Out of 62,602 participants enrolled in the NHANES study from 2007 to 2020, a total of 23,739 were included in the final analysis (Fig 1). During participant selection, data on exercise were missing for 11,740 participants, representing 19% of the total cohort. Table 1 provided a summary of the baseline characteristics of the included participants stratified by cancer status. Participants included in this study has a mean age of 46.1 years (SD = 17.5), a mean BMI of 28.7 kg/m2 (SD = 6.7) with 52.1% of female. Significant differences in baseline characteristics were observed across groups, shown in Table 1.

thumbnail
Fig 1. Flow chart for participant selection in NHANES.

NHANES, National Health and Nutrition Examination Survey.

https://doi.org/10.1371/journal.pone.0323264.g001

thumbnail
Table 1. Baseline characteristics of included participants across exercise intensity based on MET.

https://doi.org/10.1371/journal.pone.0323264.t001

Association of MET with biological ageing

The main associations between biological ageing and physical exercise were analyzed using both continuous variables (total MET per week) and binary variables (inadequate physical exercise: MET < 600 vs. adequate physical exercise: MET ≥ 600). These associations were assessed in both unadjusted linear regression models and models adjusted for covariates, as presented in Table 2. Individual with less than 600-MET physical exercise per week had a higher risk of ageing acceleration than those who had more than 600-MET physical exercise per week (MD 2.2 PhenoAge years, 95% CI [1.5–2.8], p < 0.001; MD 2.1 ENABL Age years, 95% CI [1.1–3.1], p < 0.001). In particular, each 100-MET increase per week in physical exercise was associated with delayed biological ageing by 0.2 PhenoAge years (p < 0.001), adjusted for all the measured confounding factors including sex, race, marital status, BMI, income, alcohol intake, smoking status, sleep disorder, and history of cancer, whereas each 100-MET increase in physical exercise per week was correlated with attenuated biological ageing by 0.2 ENABL Age years (p < 0.001), adjusted for the same confounding factors.

thumbnail
Table 2. Associations between MET per week with biological ageing.

https://doi.org/10.1371/journal.pone.0323264.t002

In the nonlinear association analysis, adjusted cubic spline model demonstrated a non-linear association between the total MET level and biological ageing (non-linear p < 0.001 for both PhenoAge and ENABL Age). A L-shaped association was observed in which the benefit of delayed ageing got weaker when individual’s physical exercise level exceeds the cut-off of 292-MET for PhenoAge or exceeds the cut-off of 259-MET for ENABL Age, respectively (Fig 2), where these cut-off points were calculated and generated from the cubic spline models adjusted for confounding factors.

thumbnail
Fig 2. Nonlinear associations between MET and biological age based on restricted cubic spline models.

The cubic spline models also adjusted for gender, race, BMI, sleep disorder, smoking, alcohol intake, and history of cancer. The solid blue line represents the smooth curve fit between dependent and independent variables. The grew bands represent the 95% confidence interval from the fit. (A) PhenoAge; (B) ENABL Age.

https://doi.org/10.1371/journal.pone.0323264.g002

Joint analysis of physical exercise and caffeine consumption on biological ageing

The joint associations between physical exercise and caffeine consumption was illustrated in Fig 3. We found that combination of high MET and lower caffeine consumption were associated with delayed biological ageing (MD -3.05, 95% CI = -4.41 to -1.69). Conversely, combinations of moderate and high levels of caffeine consumption attenuated the reductions in biological ageing of physical exercise, such as combination of > 600 MET and > 200 umol/L caffeine consumption (p for interaction = 0.886).

thumbnail
Fig 3. Joint association of exercise and caffeine consumption with biological ageing acceleration.

MET is categorized as low and high by the cutoff of 600 MET per week. Caffeine consumption is categorized as low, moderate, and high by the cutoff of 100 and 200 umol/L.

https://doi.org/10.1371/journal.pone.0323264.g003

Stratified subgroup analysis

The association between physical exercise level and biological age were stronger in non-Hispanic Black (MD = -4.32, 95% CI: -5.58 to -3.06) than in other races (p for interaction = 0.006) and in participants with obesity (MD = -3.48, 95% CI: -4.63 to -2.32) than in those with overweight or normal BMI (p for interaction = 0.007), which were shown in Fig 4. The magnitude of benefit observed in low-income participants (family income poverty ratio less than 1) was significantly larger (MD = -4.38, 95% CI: -6.05 to -2.72) than middle-class or rich participants (p for interaction = 0.006). Stratification analysis by history of cancer diagnosis revealed significantly different results (p for interaction = 0.035) between participants with and without cancer. The findings indicated that cancer patients did not experience significant benefits from increased physical exercise in terms of delayed ageing (MD = -0.91, 95% CI: -2.82 to 0.99). The interaction of other stratified analyses was not significant.

thumbnail
Fig 4. Subgroup analyses of associations between MET and biological age by effect modifiers of sex, race, BMI, income, sleep disorder, smoking, and self-reported cancer.

https://doi.org/10.1371/journal.pone.0323264.g004

Sensitivity analysis

The pre-specified sensitivity analyses did not change the observed results. A similar pattern of associations between physical exercise level and delayed ageing was observed in all sensitivity analyses, including regression models after excluding cancer patients, association analyses using various physical exercise level measurement approaches (MET per week, vigorous intensity activity minutes per week, vigorous intensity activity minutes per day), and using different physical exercise level category ascertainment approaches (MET ≥ 600 per week, vigorous intensity activity ≥ 75 minutes per week, vigorous intensity activity ≥ 30 minutes per day) (S1 Table and S2 Table).

Discussion

In our study, we conducted a cross-sectional analysis to explore the correlation between physical activity levels (measured in MET) and biological ageing using data from the NHANES study. Our findings revealed that higher MET levels were associated with delayed biological ageing in adults without cancer. Specifically, participants who engaged in more than 600 MET of exercise per week exhibited delayed biological ageing by an average of 2.2 years compared to those with less than 600 MET per week. Notably, stronger benefits of biological ageing deceleration were observed among individuals of non-Hispanic Black ethnicity, those with obesity, and those with lower income levels. Furthermore, our results suggest that cancer patients might not experience significant benefits from higher levels of physical exercise in terms of biological ageing.

The results of this study align with previous research indicating that exercise can decelerate the ageing process through various mechanisms. In mouse models, running has been shown to reduce leptin production in adipose tissue, decrease hematopoietic activity, and subsequently lower chronic inflammation [27]. Another study in mice demonstrated that exercise not only mitigated the upregulation of inflammatory pathways in older mice but also restored intercellular communication within stem cell compartments through immune cells [28]. A pilot study involving 45 participants found that moderate-to-vigorous physical activity attenuated the premature senescence of immune cells [29]. A population-based study revealed that different exercise patterns were associated with ageing outcomes, such as the correlation of leisure walking with delayed ageing and job-related physical activities with accelerated ageing [30]. Additionally, a cohort study in Germany found that MET levels were linked to ageing-related epigenetic features, as measured by DNA methylation sequencing [31].

Non-linear correlation interpretation

The non-linear correlation between physical exercise levels and biological ageing may be explained by recent findings suggesting that vigorous exercise can increase biomarkers of cardiomyocyte injury, indicating that lifelong endurance exercise may contribute to myocardial scarring [32]. This raises the possibility that higher levels of physical exercise (e.g., exceeding 292 MET for PhenoAge or 259 MET for ENABL Age) may induce other forms of bodily damage, potentially offsetting the beneficial effects of exercise on biological ageing. For instance, in the context of neuro-ageing, a cross-sectional study found that high-intensity physical activity was not associated with improved cognitive performance in older adults [33]. Our findings regarding the non-linear relationship suggest that the beneficial effects of exercise may vary across different activity intensities, highlighting the need for a balanced approach to physical activity.

Effect modification interpretation

The differential benefits of physical exercise on biological ageing among non-Hispanic Black individuals, those with obesity, and low-income populations, as well as the lack of benefit observed in cancer patients, can be attributed to several factors. Non-Hispanic Black individuals experience greater delays in biological ageing compared to other racial groups, which may be partially explained by a metabolic profiling study showing that metabolite responses to physical activity are dose-sensitive and vary by race, with Black populations exhibiting a more pronounced response than White populations [34]. For individuals with obesity, a Mendelian randomization study demonstrated a causal link between overweight status and accelerated biological ageing [35], suggesting that physical exercise may decelerate ageing through weight loss as a mediating factor. Regarding socioeconomic status, a secondary analysis of the NHANES study revealed a positive correlation between higher income and greater physical activity levels in adolescents and young adults [36], while a longitudinal U.S. study from 2001 to 2014 found that higher income was associated with increased longevity [37]. The economic principle of diminishing marginal utility may explain why low-income individuals, despite having fewer resources for exercise facilities, experience greater benefits in terms of delayed biological ageing. This reflects the idea that providing additional benefits to those with fewer resources (e.g., low-income individuals) yields greater overall impact compared to those who already have ample resources (e.g., high-income individuals) [38,39].

Cancer population interpretation

Although an analysis of the Global Burden of Disease (GBD) study found that physical exercise is inversely correlated with the risk of breast, lung, gastric, liver, and colon cancers [40], this does not necessarily imply that individuals diagnosed with cancer can still benefit from physical exercise, particularly those experiencing cancer-related fatigue following surgery, chemotherapy, or other treatments. The overlapping hallmarks of ageing and cancer provide valuable insights into understanding the complex relationship between exercise levels and biological ageing in cancer patients [41]. Among the 12 hallmarks of ageing, genomic instability, epigenetic alterations, chronic inflammation, and dysbiosis share commonalities with cancer, exerting similar directional effects. However, telomere attrition and stem cell exhaustion, which accelerate ageing, paradoxically suppress oncogenesis. Additionally, disabled macro-autophagy and cellular senescence, which promote ageing, exhibit scenario-dependent effects that can either support or inhibit tumorigenesis. The intricate interplay of these hallmarks partly explains the complicated relationship between physical exercise and biological ageing in cancer patients.

Interaction with caffeine

Joint analysis revealed that caffeine consumption did not modify the correlation between physical exercise and biological ageing, as no interaction between caffeine consumption and physical exercise was observed—contrary to our initial assumption. A previous epidemiological study using NHANES data found that caffeine intake was inversely associated with telomere length, while coffee consumption was positively correlated with telomere length [42]. This discrepancy may explain why moderate and high levels of caffeine consumption attenuated the positive correlation between physical exercise and biological ageing. The underlying mechanism of physical exercise’s effect on biological ageing is related to mechanotransduction, a process by which organisms convert mechanical loading into cellular responses [43]. In contrast, caffeine, a 1,3,7-trimethylxanthine, functions as a non-selective adenosine receptor antagonist, affecting multiple systems in the body [44]. Although previous research has demonstrated that caffeine intake can enhance physical exercise performance [45], our study did not observe any interaction between caffeine consumption and physical exercise in terms of biological ageing.

What have been reported regarding the relationship between physical exercise, caffeine intake, and biological ageing were summarized in Table 3.

thumbnail
Table 3. Summary of studies investigating association of exercise, caffeine, and ageing.

https://doi.org/10.1371/journal.pone.0323264.t003

Strengths and limitations

Strengths of this study include the following points. First, we utilized the NHANES dataset, which features a large sample size and long survey periods, providing sufficient statistical power for our analyses. NHANES’s weighted sampling methods ensure that our study sample is representative of the entire U.S. population. Second, we conducted subgroup analyses to explore potential effect modifiers and sensitivity analyses to confirm the consistency of our findings, thereby enhancing the robustness of our results and conclusions. This study also had the following limitations. First, due to the nature of cross-sectional studies, we cannot establish causal relationships between physical exercise and delayed biological ageing. The observed non-linear associations are exploratory and require further validation. Second, although we controlled for potential confounding factors as covariates in our regression models, residual and unmeasured confounding factors might still bias our results. Third, phenotype and biomarker data for biological ageing were only available at one time point, limiting our ability to capture and investigate changes in biological ageing over time. Forth, physical activity levels were calculated based on self-reported questionnaires about daily or weekly habits, which may introduce information and measurement errors, potentially biasing our results. Finally, the finding that more than 600 METs of physical exercise per week was associated with an average of 2.2 years of delayed biological ageing should be interpreted cautiously. The effects of physical activity on biological ageing are likely not immediate but may manifest as aftereffects or long-term outcomes.

Conclusions

In conclusion, our findings indicate a positive correlation between higher levels of physical exercise per week and delayed biological ageing among U.S. adults without cancer. However, the benefits of delayed ageing diminish at higher MET levels of physical exercise, and caffeine intake does not modify this correlation. Physical exercise exceeding 600 METs per week—equivalent to 75 minutes of vigorous-intensity or 150 minutes of moderate-intensity activity per week—may be particularly advantageous in decelerating biological ageing as part of healthy ageing management. These findings are constrained by the limitations of the cross-sectional design and the inability to establish causal relationships. Nevertheless, the results hold significant implications for public health strategies aimed at promoting healthy ageing through appropriate levels of physical activity. Further validation using prospective cohort studies or interventional trials is warranted to confirm these observations.

Supporting information

Checklist. STROBE statement.

An Explanation and Elaboration article discusses each checklist item and gives methodological background and published examples of transparent reporting. The STROBE checklist is best used in conjunction with this article (freely available on the Web sites of PLoS Medicine at http://www.plosmedicine.org/, Annals of Internal Medicine at http://www.annals.org/, and Epidemiology at http://www.epidem.com/). Information on the STROBE Initiative is available at www.strobe-statement.org.

https://doi.org/10.1371/journal.pone.0323264.s001

(DOCX)

S1 Table. Sensitivity analyses of associations between MET and biological age excluding participants with cancer.

Model I: raw model without covariates to adjust; Model II: adjusted for gender, race, marital status, income; Model III: adjusted for covariates in model II and BMI, sleep disorder, smoking, alcohol intake, history of cancer. The independent variable unit is per 100-MET change in all models. MET, metabolic equivalent of task.

https://doi.org/10.1371/journal.pone.0323264.s002

(DOCX)

S2 Table. Sensitivity analyses of associations between physical activity with biological ageing.

Model I: raw model without covariates to adjust; Model II: adjusted for gender, race, marital status, income; Model III: adjusted for covariates in model II and BMI, sleep disorder, smoking, alcohol intake, history of cancer. MET, metabolic equivalent of task. Vigorous activities per day > 75 minutes or moderate activities per day > 150 minutes as high intensity; low intensity otherwise.

https://doi.org/10.1371/journal.pone.0323264.s003

(DOCX)

Acknowledgments

None.

References

  1. 1. López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. The hallmarks of aging. Cell. 2013;153(6):1194–217. pmid:23746838
  2. 2. López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023;186(2):243–78. pmid:36599349
  3. 3. Oh HS, Rutledge J, Nachun D, et al. Organ ageing signatures in the plasma proteome track health and disease. Nature. 2023;624(7990):164–72.
  4. 4. Moqri M, Herzog C, Poganik JR, et al. Validation of biomarkers of ageing. Nat Med. 2024;14: 1–3.
  5. 5. Hannum G, Guinney J, Zhao L, Zhang L, Hughes G, Sadda S, et al. Genome-wide methylation profiles reveal quantitative views of human aging rates. Mol Cell. 2013;49(2):359–67. pmid:23177740
  6. 6. Jurić J, Kohrt WM, Kifer D, Gavin KM, Pezer M, Nigrovic PA, et al. Effects of estradiol on biological age measured using the glycan age index. Aging (Albany NY). 2020;12(19):19756–65. pmid:33049709
  7. 7. Lu AT, Quach A, Wilson JG, Reiner AP, Aviv A, Raj K, et al. DNA methylation GrimAge strongly predicts lifespan and healthspan. Aging (Albany NY). 2019;11(2):303–27. pmid:30669119
  8. 8. Liu Z, Kuo P-L, Horvath S, Crimmins E, Ferrucci L, Levine M. A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV: A cohort study. PLoS Med. 2018;15(12):e1002718. pmid:30596641
  9. 9. Qiu W, Chen H, Kaeberlein M, Lee S-I. ExplaiNAble BioLogical Age (ENABL Age): an artificial intelligence framework for interpretable biological age. Lancet Healthy Longev. 2023;4(12):e711–23. pmid:37944549
  10. 10. Moqri M, Herzog C, Poganik JR, Biomarkers of Aging Consortium, Justice J, Belsky DW, et al. Biomarkers of aging for the identification and evaluation of longevity interventions. Cell. 2023;186(18):3758–75. pmid:37657418
  11. 11. Guo J, Huang X, Dou L, Yan M, Shen T, Tang W, et al. Aging and aging-related diseases: from molecular mechanisms to interventions and treatments. Signal Transduct Target Ther. 2022;7(1):391. pmid:36522308
  12. 12. Kehler DS. Age-related disease burden as a measure of population ageing. Lancet Public Health. 2019;4(3):e123–4. pmid:30851865
  13. 13. Chen Z, Chen Z, Jin X. Mendelian randomization supports causality between overweight status and accelerated aging. Aging Cell. 2023;22(8):e13899. pmid:37277933
  14. 14. He H, Chen X, Ding Y, Chen X, He X. Composite dietary antioxidant index associated with delayed biological aging: A population-based study. Aging (Albany NY). 2024;16(1):15–27. pmid:38170244
  15. 15. Brassen S, Gamer M, Peters J, Gluth S, Büchel C. Don’t look back in anger! Responsiveness to missed chances in successful and nonsuccessful aging. Science. 2012;336(6081):612–4. pmid:22517323
  16. 16. Leng Y, Musiek ES, Hu K, Cappuccio FP, Yaffe K. Association between circadian rhythms and neurodegenerative diseases. Lancet Neurol. 2019;18(3):307–18. pmid:30784558
  17. 17. Guarente L, Sinclair DA, Kroemer G. Human trials exploring anti-aging medicines. Cell Metab. 2024;36(2):354–76. pmid:38181790
  18. 18. Wu R, Sun F, Zhang W, Ren J, Liu G-H. Targeting aging and age-related diseases with vaccines. Nat Aging. 2024;4(4):464–82. pmid:38622408
  19. 19. Keshavarz M, Xie K, Schaaf K, Bano D, Ehninger D. Targeting the “hallmarks of aging” to slow aging and treat age-related disease: fact or fiction?. Mol Psychiatry. 2023;28(1):242–55. pmid:35840801
  20. 20. Bull FC, Al-Ansari SS, Biddle S, Borodulin K, Buman MP, Cardon G, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451–62. pmid:33239350
  21. 21. Piercy KL, Troiano RP, Ballard RM, Carlson SA, Fulton JE, Galuska DA, et al. The physical activity guidelines for Americans. JAMA. 2018;320(19):2020–8. pmid:30418471
  22. 22. Rock CL, Thomson CA, Sullivan KR, Howe CL, Kushi LH, Caan BJ, et al. American Cancer Society nutrition and physical activity guideline for cancer survivors. CA Cancer J Clin. 2022;72(3):230–62. pmid:35294043
  23. 23. Lucía A, Earnest C, Pérez M. Cancer-related fatigue: can exercise physiology assist oncologists?. Lancet Oncol. 2003;4(10):616–25. pmid:14554239
  24. 24. Liu D, Xie F, Zeng N, Han R, Cao D, Yu Z, et al. Urine caffeine metabolites are positively associated with cognitive performance in older adults: An analysis of US National Health and Nutrition Examination Survey (NHANES) 2011 to 2014. Nutr Res. 2023;109:12–25. pmid:36543015
  25. 25. Sampaio-Jorge F, Morales AP, Pereira R, Barth T, Ribeiro BG. Caffeine increases performance and leads to a cardioprotective effect during intense exercise in cyclists. Sci Rep. 2021;11(1):24327. pmid:34934054
  26. 26. Zhao Z, Zhou J, Shi A, Wang J, Li H, Yin X, et al. Per- and poly-fluoroalkyl substances (PFAS) accelerate biological aging mediated by increased C-reactive protein. J Hazard Mater. 2024;480:136090. pmid:39405719
  27. 27. Frodermann V, Rohde D, Courties G, Severe N, Schloss MJ, Amatullah H, et al. Exercise reduces inflammatory cell production and cardiovascular inflammation via instruction of hematopoietic progenitor cells. Nat Med. 2019;25(11):1761–71. pmid:31700184
  28. 28. Liu L, Kim S, Buckley MT, Reyes JM, Kang J, Tian L, et al. Exercise reprograms the inflammatory landscape of multiple stem cell compartments during mammalian aging. Cell Stem Cell. 2023;30(5):689–705.e4. pmid:37080206
  29. 29. Chen X-K, Zheng C, Wong SH-S, Ma AC-H. Moderate-vigorous physical activity attenuates premature senescence of immune cells in sedentary adults with obesity: a pilot randomized controlled trial. Aging (Albany NY). 2022;14(24):10137–52. pmid:36585923
  30. 30. Zhu J, Yang Y, Zeng Y, et al. The association of physical activity behaviors and patterns with ageing acceleration: Evidence from the UK Biobank. J Gerontol A Biol Sci Med Sci. 2023;78(5):753–61.
  31. 31. Fox FAU, Liu D, Breteler MMB, Aziz NA. Physical activity is associated with slower epigenetic ageing-findings from the Rhineland study. Aging Cell. 2023;22(6):e13828. pmid:37036021
  32. 32. Thompson PD, Eijsvogels TMH, Kim JH. Can the heart get an overuse sports injury?. NEJM Evid. 2022;2(1):EVIDra2200175. pmid:38320102
  33. 33. Wu Z, Zhang H, Miao X, Li H, Pan H, Zhou D, et al. High-intensity physical activity is not associated with better cognition in the elder: evidence from the China Health and Retirement Longitudinal Study. Alzheimers Res Ther. 2021;13(1):182. pmid:34732248
  34. 34. Du Y, Li Y-Y, Choi BY, Fernadez R, Su K-J, Sharma K, et al. Metabolomic profiles associated with physical activity in White and African American adult men. PLoS One. 2023;18(11):e0289077. pmid:37943870
  35. 35. Chen Z, Chen Z, Jin X. Mendelian randomization supports causality between overweight status and accelerated ageing. Ageing Cell. 2023;22(8):e13899.
  36. 36. Armstrong S, Wong CA, Perrin E, Page S, Sibley L, Skinner A. Association of physical activity with income, race/ethnicity, and sex among adolescents and young adults in the United States: findings from the National Health and Nutrition Examination Survey, 2007-2016. JAMA Pediatr. 2018;172(8):732–40.
  37. 37. Chetty R, Stepner M, Abraham S, et al. The association between income and life expectancy in the United States, 2001-2014. JAMA. 2016;315(16):1750–66.
  38. 38. Waugh N, Scott D. How should different life expectancies be valued?. BMJ. 1998;316(7140):1316. pmid:9554908
  39. 39. Bassoli E. An empirical analysis of health-dependent utility on SHARE and ELSA data. Ital Econ J. 2022;9(3):1217–61.
  40. 40. Diao X, Ling Y, Zeng Y, Wu Y, Guo C, Jin Y, et al. Physical activity and cancer risk: a dose-response analysis for the Global Burden of Disease Study 2019. Cancer Commun (Lond). 2023;43(11):1229–43. pmid:37743572
  41. 41. López-Otín C, Pietrocola F, Roiz-Valle D, Galluzzi L, Kroemer G. Meta-hallmarks of aging and cancer. Cell Metab. 2023;35(1):12–35. pmid:36599298
  42. 42. Tucker LA. Caffeine consumption and telomere length in men and women of the National Health and Nutrition Examination Survey (NHANES). Nutr Metab (Lond). 2017;14:10. pmid:28603543
  43. 43. Chen J, Zhou R, Feng Y, Cheng L. Molecular mechanisms of exercise contributing to tissue regeneration. Signal Transduct Target Ther. 2022;7(1):383. pmid:36446784
  44. 44. Carman AJ, Dacks PA, Lane RF, Shineman DW, Fillit HM. Current evidence for the use of coffee and caffeine to prevent age-related cognitive decline and Alzheimer’s disease. J Nutr Health Aging. 2014;18(4):383–92. pmid:24676319
  45. 45. Martins GL, Guilherme JPLF, Ferreira LHB, de Souza-Junior TP, Lancha AH Jr. Caffeine and exercise performance: Possible directions for definitive findings. Front Sports Act Living. 2020;2:574854. pmid:33345139