Wellness Check: Exercise

Aerobic and strengthening physical activity may have a dose-response association with mortality

1. In this study, compared to no aerobic physical activity (PA), substantial mortality risk reduction was associated with 1 hour/week of aerobic PA and levelled off at 3 hours/week.
2. Muscle strengthening exercise (MSE) conferred additional mortality risk reduction at 1 time/week, but was no longer beneficial at 7 times/week.

Evidence Rating Level: 2 (Good)

Despite its numerous benefits, more than 1 billion adults do not meet the standard World Health Organization recommendations. Although recent analyses have examined the association between physical activity and all-cause mortality risk, minimal evidence exists surrounding minimum effective doses. As a result, the objective of the present prospective cohort study was to identify the dose-response association and minimum effective doses of aerobic PA and MSE required to result in a clinically significant lower all-cause mortality risk.

The present study used National Health Interview Survey data (1997-2014) and included 416 420 adults from the United States (US). Participants were excluded if they were not permanent residents of the United States, were in correctional facilities, active duty military, or in long-term care facilities. Activity levels were reported using a standardized questionnaire. The study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Cox proportional-hazard models were used to evaluate the association between physical activity and all-cause mortality.

Results demonstrated that compared to no aerobic PA, substantial mortality risk reduction was associated with 1 hour/week of aerobic PA and levelled off at 3 hours/week. Muscle strengthening exercise (MSE) conferred additional mortality risk reduction at 1 time/week but was no longer beneficial at 7 times/week. Despite these results, the study was limited by the self-reported nature of physical activity. Nevertheless, this longitudinal analysis of data from a large sample of US adults allowed for a greater understanding of the relationship between PA/MSE and mortality, and may inform US healthcare providers.

Regular physical activity may confer protection against adverse COVID-19 outcomes

1. In this study, engaging in regular physical activity had a lower risk of infection, hospitalization, severe COVID-19 illness, and COVID-19 related death compared to inactive peers.

2. The greatest benefit was achieved at 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week.

Evidence Rating Level: 1 (Excellent)

Physical activity is known to have a multitude of beneficial health effects as well as enhancing immunity. To date, the link between regular physical activity and COVID-19 outcomes has been poorly understood. As a result, the aim of the present systematic review and meta-analysis was to quantify the association between physical activity and the risk of COVID-19 infection, hospitalization, severe illness and death in adults.

Of 4063 identified records, 16 studies were included in the systematic review (n=1 853 610) from database inception to March 2022. Studies were eligible if they studied the effects of physical activity (questionnaires or objective measures) on COVID-19 outcomes. Studies were excluded If participants self-reported COVID-19 infection or were hospitalized. Quality of the evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to evaluate. Statistical analysis was performed using a random-effects inverse-variance model.

Results demonstrated that engaging in regular physical activity had a lower risk of infection, hospitalization, severe COVID-19 illness, and COVID-19 related death compared to inactive peers. Furthermore, the greatest benefit was achieved at 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week. Despite these findings, the study was limited by the potential for the pooled estimates to be confounded. Nonetheless, these results may help guide physicians in encouraging physical activity among patients to reduce the burden of COVID-19 health outcomes.

Occupational and leisure physical activity may have varying effects on inflammation 

1. Lower leisure time physical activity and higher occupational physical activity were associated with increased high-sensitivity C reactive protein (hs-CRP) levels.
2. When analyzed as continuous variables, only leisure time physical activity was strongly associated with hs-CRP levels.

Evidence Rating Level: 2 (Good)

Paradoxically, physical activity associated with one’s occupation has been shown in the literature to increase cardiovascular disease and mortality; a finding that does not hold true for physical activity associated with leisure. Though many mechanisms have been proposed, sustained systemic inflammation (measured through hs-CRP levels) may be an important contributor. In order to further study this association, the objective of the present cross-sectional study was to determine the extent to which physical activity performed during work and leisure time was associated with systemic inflammation.

The present study used data from the Copenhagen Aging and Midlife Biobank (CAMB) cohort. Of 12656 invited participants, 5304 had blood samples taken, including the hs-CRP biomarker. Occupational physical activity was measured based on self-reported job history with a job exposure matrix. Leisure time physical activity was self-reported using the CAMB questionnaire. The association between the two types of physical activity and hs-CRP was done using multivariable linear regression models as well as post-hoc analyses.

Results demonstrated that lower leisure time physical activity and higher occupational physical activity were associated with increased high-sensitivity C reactive protein (hs-CRP) levels. Furthermore, when analyzed as continuous variables, only leisure time physical activity was strongly associated with hs-CRP levels. Despite these findings, the study was limited by the risk of misclassification, as physical activity was based on job title. Nonetheless, the inclusion of a large number of participants strengthened the findings of the present study and the fact that systemic inflammation may in fact explain the physical activity paradox.

Lower limb osteoarthritis may be more prevalent in retired Olympians

1. In this study, one in four retired Olympians reported physician-diagnosed osteoarthritis (OA), with injury being associated with an increased risk of OA and pain at the knee, hip, and ankle.
2. After adjusting for risk factors, Olympians were more likely to have knee and hip OA after injury compared to the general population.

Evidence Rating Level: 3 (Average)

Joint injury may be a risk factor for future development of OA, especially for elite sport participants. To date, few studies have compared the magnitude of OA in different body sites in elite athletes (such as Olympians) and the general population. As a result, the objective of the present cross-sectional study was to compare the prevalence of lower limb physician-diagnosed OA and pain in retired Olympians, as well as determine contributing factors.

The present study included self-reported data from an online survey administered to Olympians (through Olympic association platforms) and the general population (in three different phases). 3357 retired Olympians (median age= 44.7 years) and 1735 (median age= 40.5 years) individuals from the general population completed the survey between April 2018 and June 2019. Retired Olympians had to be 16 years or older and competed in at least one summer/and or winter Olympic game. General population controls included those older than 16 years who did not compete in the Olympics. For statistical analyses, independent t-tests, Mann-Whitney U tests, Chi-square testing and logistic regression were used.

Results demonstrated that one in four retired Olympians reported physician-diagnosed osteoarthritis (OA), and injury was associated with an increased risk of OA and pain at the knee, hip and ankle. Furthermore, after adjusting for risk factors, Olympians were more likely to have knee and hip OA after injury, compared to the general population. Despite these results, the study was limited by only representing 4% of the total retired Olympian population. Nonetheless, the present results may help inform prevention strategies to reduce the risk of lower limb OA in Olympians after retirement from their sport.

Image: PD

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