Physical activity paradox: could inflammation be a key factor?

Joint associations of sedentary behavior and domain-specific physical activity on C-reactive protein in Korea

Sedentary behavior (SB) and physical activity (PA) exert opposing effects on inflammatory markers. This study examined the associations of a more subdivided combination of PA and SB with high-sensitivity C-reactive protein (hs-CRP). Using the 2014-2019 Korean National Health and Nutrition Examination Survey, this cross-sectional study analyzed 20,541 adults. The independent variables were SB, defined as ≥10 h of sitting per day, and three domains of PA: occupational PA (OPA) during work, leisure-time PA (LPA) during leisure time, and transportation PA (TPA) or active commuting. The dependent variable was hs-CRP ≥ 1.0 mg/L. Besides exploring the individual association of SB and each PA with hs-CRP, the combined association of SB and each PA with hs-CRP was also examined using multiple logistic regression. The analyses indicated that concurrent exposure to SB and OPA (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.02-1.80) significantly raised the likelihood of increased hs-CRP, while SB without LPA (OR 1.26, 95% CI 1.11-1.41) or TPA (OR 1.19, 95% CI 1.08-1.31) significantly increased risk of higher hs-CRP, compared to their respective reference. The absence of non-occupational PA such as LPA or TPA combined with SB was associated with the increased hs-CRP risk, whereas OPA increased the risk when present concurrently with SB. Reducing SB and OPA while increasing LPA and TPA, is necessary to reduce inflammatory conditions.

Physical Activity and High-Sensitivity C-Reactive Protein in Pregnancy: Does It Matter during Leisure or Work?

INTRODUCTION

Physical activity (PA), regardless of domain, is recommended for pregnant individuals in clinical guidelines, but limited evidence is available for work-related PA. This study aimed to examine the associations of occupational (OPA) and leisure-time PA (LTPA) with plasma high-sensitivity C-reactive protein (hs-CRP), a risk marker for adverse pregnancy outcomes, among pregnant individuals.

METHODS

This longitudinal study included 257 workers in the fetal growth cohort. OPA/LTPA and hs-CRP were measured in each trimester. OPA/LTPA was divided into high and low groups by the median level. Multivariable linear regressions were applied to estimate the adjusted geometric mean differences of hs-CRP (mg·L-1) comparing high versus low OPA/LTPA in each trimester and the changes in OPA/LTPA over pregnancy.

RESULTS

OPA was positively associated with hs-CRP (high: 5.14 vs low: 3.59; P value: 0.001) in the first trimester, particularly for standing/walking or walking fast, regardless of carrying things. LTPA was negatively associated with hs-CRP in the second (high: 3.93 vs low: 5.08; 0.02) and third trimesters (high: 3.30 vs low: 4.40; 0.046). Compared with the low OPA + high LTPA group, hs-CRP was higher in both the high OPA + high LTPA and high OPA + low LTPA groups in the first trimester, and in the high OPA + low LTPA group only in the third trimester. The change in OPA during pregnancy was positively associated with hs-CRP, whereas the change in LTPA was negatively associated with hs-CRP from the second to the third trimester.

CONCLUSIONS

In pregnant individuals, LTPA was negatively associated with hs-CRP, whereas OPA was positively associated with hs-CRP. More research on OPA's health impact among pregnant individuals is needed, and guidelines may consider the potential unfavorable influence of OPA on pregnant individuals.

Occupational physical activity: the good, the bad, and the proinflammatory

Background

Physical activity (PA) is beneficial for preventing several conditions associated with underlying chronic inflammation, e. g., cardiovascular disease (CVD) and cancer. While an active lifestyle appears to have anti-inflammatory effects, high levels of occupational PA (OPA) were associated with inflammation and elevated mortality risks. We aimed to summarize the current knowledge (1) on the association between inflammation and OPA and (2) its implications for health and mortality.

Methods and results

This mini-review summarized relevant literature published before January 2023 using established scientific databases and sources. For the primary outcome, observational studies (S) reporting immunological effects (O) in subjects (P), with high (I) vs. low OPA (C), were included. For secondary outcomes, i.e., morbidity and mortality associated with inflammatory processes, (systematic) reviews were included. While "active" occupations and "moderate" OPA appear to have beneficial effects, low (particularly sedentary) and "high-intensity" OPA (particularly including heavy lifting tasks) were associated with inflammation and (CVD and cancer-related) mortality; higher leisure-time PA has been almost consistently associated with lower proinflammatory markers and all-cause mortality risks. Workplace interventions appear to counter some of the observed health effects of unfavorable work strain.

Conclusion

The few studies addressing OPA "intensity" and inflammatory markers are largely heterogeneous regarding OPA classification and confounder control. Sedentary and "heavy" OPA appear to promote proinflammatory effects. In addition to targeted management of work-related physical strain and hazardous environmental co-factors, occupational health providers should focus on employer-initiated exercise interventions and the promotion of leisure-time PA.

How Does Occupational Lifting Affect Ambulatory Blood Pressure, Relative Aerobic Workload and Level of Physical Activity?

INTRODUCTION

Occupational physical activity (OPA), including occupational lifting (OL), seems to increase the risk of cardiovascular disease (CVD). Knowledge about the association between OL and risk of CVD is sparse, but repeated OL is assumed to result in prolonged raised blood pressure and heart rate (HR) eventually augmenting the risk of CVD. To disentangle parts of the mechanisms behind the raised 24-hour ambulatory blood pressure measurement (24h-ABPM), by exposure to OL, this study aimed to explore the acute differences in 24h-ABPM, relative aerobic workload (RAW) and OPA across workdays with and without OL, and secondary to assess the feasibility and rater agreement of direct field observations of the frequency and load of occupational lifting.

METHODS

This controlled cross-over study investigates associations between moderate to high OL and 24h-ABPM, RAW in per cent of heart rate reserve (%HRR) and level of OPA. This included 2x24h monitoring of 24h-ABPM (Spacelabs 90217), PA (Axivity) and HR (Actiheart), comprising a workday containing OL and a workday without. The frequency and burden of OL were directly observed in field. The data were time synchronized and processed in the Acti4 software. Differences across workdays with and without OL in 24h-ABPM, RAW and OPA were evaluated using repeated 2 × 2 mixed-models among 60 blue-collar workers in Denmark.. Exposure to OL was estimated by direct manual field observation, registering burden and frequency of OL. Interrater reliability tests were performed across 15 participants representing 7 occupational groups. Interclass correlation coefficient (ICC) estimates of total burden lifted and frequency of lifts were calculated, based on a mean-rating (k = 2), absolute-agreement, 2 way mixed-effects model, indicating the raters as fixed effects.

RESULTS

OL led to non-significant increases in ABPM during work-time (systolic Δ1.79 mmHg, 95%CI -4.49-8.08, diastolic Δ0.43 mmHg, 95%CI -0.80-1.65), and on 24-hours basis (systolic Δ1.96 mmHg, 95%CI -3.80-7.72, diastolic Δ0.53 mmHg, 95%CI -3.12-4.18), significant increases in RAW during work (Δ7.74 %HRR, 95%CI 3.57-11.91) as well as a raised level of OPA (Δ4156.88 steps, 95%CI 1898.83-6414.93, Δ-0.67 hours of sitting time, 95%CI -1.25-0.10, Δ-0.52 hours of standing time, 95%CI -1.03-0.01, Δ0.48 hours of walking time, 95%CI 0.18-0.78). ICC estimates were 0.998 (95% CI 0.995-0.999) for total burden lifted and 0.992 (95% CI 0.975-0.997) for frequency of lift.

DISCUSSION

OL increased both intensity and volume of OPA among blue-collar workers, which supposedly to contributes to an augmented risk of CVD. Although this study finds hazardous acute effects, further investigations are needed to evaluate the long-term effects of OL on ABPM, HR and volume of OPA, also effects of cumulative exposure to OL would be relevant to investigate.

CONCLUSION

OL significantly raised the intensity and volume of OPA. Direct field observation of occupational lifting showed an excellent interrater reliability.

The association between physical activity, low-grade inflammation, and labour market attachment among people with multimorbidity: A cross-sectional study from the Lolland-Falster Health Study, Denmark

Aim

Evidence suggests low-grade inflammation (LGI) to be associated with multimorbidity. Furthermore, there are links between inflammation markers, physical activity (PA), and labour market participation. The aims of this study were to examine the association between PA and LGI in people with multimorbidity and if this association was moderated by self-reported labour market attachment.

Methods

Cross-sectional data were collected in the Lolland-Falster Health Study (LOFUS) from 2016-2020. We included 1,106 participants with multimorbidity and valid accelerometer data. PA was measured as the average counts per minute (CPM) per day during wake time and split in time spent in moderate to vigorous intensity (MVPA) and light intensity (LPA). Degree of inflammation was determined by high sensitive C-reactive protein (hsCRP) level. Associations were investigated using multiple logistic regression analyses, stratified by labour market attachment.

Results

The odds of having LGI was higher with lower amount of daily LPA. The highest odds of LGI was observed for CPM < 200 per day (odds ratio (OR) 2.55; 95% confidence interval (CI) 1.46-4.43), MVPA < 15 minutes per day (OR 2.97; 95 % CI 1.56-5.62), and LPA < 90 (OR 2.89; 95 % CI 1.43-5.81) with the reference groups being CPM ≥ 400 per day, MVPA ≥ 30, and LPA ≥ 180 min per day, respectively. We could not preclude an interaction between LPA and labour market attachment (p = 0.109).

Conclusion

PA recommendations should be developed with attention to people with chronic diseases, who may experience barriers to reach PA at high intensities. People with no labour market attachment may benefit from primary and secondary prevention of multimorbidity.