Cardiorespiratory fitness and lifestyle on severe COVID-19 risk in 279,455 adults: a case control study

Abstract

Background The impact of cardiorespiratory fitness (CRF) and other lifestyle-related factors on severe COVID-19 risk is understudied. The present study aims to investigate lifestyle-related and socioeconomic factors as possible predictors of COVID-19, with special focus on CRF, and to further study whether these factors may attenuate obesity- and hypertension-related risks, as well as mediate associations between socioeconomic factors and severe COVID-19 risk. Methods Out of initially 407,131 participants who participated in nationwide occupational health service screening between 1992 and 2020, n = 857 cases (70% men, mean age 49.9 years) of severe COVID-19 were identified. CRF was estimated using a sub-maximum cycle test, and other lifestyle variables were self-reported. Analyses were performed including both unmatched, n = 278,598, and sex-and age-matched, n = 3426, controls. Severe COVID-19 included hospitalization, intensive care or death due to COVID-19. Results Patients with more severe COVID-19 had significantly lower CRF, higher BMI, a greater presence of comorbidities and were more often daily smokers. In matched analyses, there was a graded decrease in odds for severe COVID-19 with each ml in CRF (OR = 0.98, 95% CI 0.970 to 0.998), and a two-fold increase in odds between the lowest and highest (< 32 vs. ≥ 46 ml·min−1·kg−1) CRF group. Higher BMI (per unit increase, OR = 1.09, 1.06 to 1.12), larger waist circumference (per cm, OR = 1.04, 1.02 to 1.06), daily smoking (OR = 0.60, 0.41 to 0.89) and high overall stress (OR = 1.36, 1.001 to 1.84) also remained significantly associated with severe COVID-19 risk. Obesity- and blood pressure-related risks were attenuated by adjustment for CRF and lifestyle variables. Mediation through CRF, BMI and smoking accounted for 9% to 54% of the associations between low education, low income and blue collar/low skilled occupations and severe COVID-19 risk. The results were consistent using either matched or unmatched controls. Conclusions Both lifestyle-related and socioeconomic factors were associated with risk of severe COVID-19. However, higher CRF attenuated the risk associated with obesity and high blood pressure, and mediated the risk associated with various socioeconomic factors. This emphasises the importance of interventions to maintain or increase CRF in the general population to strengthen the resilience to severe COVID-19, especially in high-risk individuals.

Baseline physical activity is associated with reduced mortality and disease outcomes in COVID‐19: A systematic review and meta‐analysis

“…Six studies involving 130,774 cases (77,435 physically active cases and 53,339 control cases) were included. 8 , 14 , 16 , 17 , 18 , 19 The random‐effect model showed that PA was associated with reduction in COVID‐19 ICU admissions compared with control (RR = 0.65, 95% CI 0.52–0.81, P = 0.0001). The value of I 2 = 73% indicated that significant heterogeneity exists in the included studies ( P = 0.0001; Figure 3a ).…”

“… 26 Additionally, it has a protective impact on COVID‐19 risk factors such as obesity and hypertension. 9 , 14 Furthermore, we previously reported that a sedentary lifestyles increase the risk of COVID‐19 severity and mortality. 16 Further, high hospitalisation rates have been reported in patients with less cardiorespiratory fitness.…”

“… 15 Different mechanisms may explain the protective effect of PA on COVID‐19 outcomes and disease severity. 14 Regular PA improves immune function, and regularly active individuals have a lower incidence, intensity of symptoms, and mortality from COVID‐19 and other various viral infections. 22 , 23 , 24 , 25 Moreover, regular PA reduces the risk of systemic inflammation, which is considered the primary contributor to lung damage in COVID‐19 patients.…”

Association of physical activity and the risk of COVID-19 hospitalization: a dose–response meta-analysis

“…The steps for retrieval and inclusion are shown in Fig 1 . The characteristics of the literature are listed in Table 1. Among the 17 studies, 3 were from North America [10,19,20], 7 were from Asia [11,12,21,22,23,24,25], 6 were from Europe [26,27,28,29,30,31], and 1 was from Oceania [32]. The NOS was used to score the included studies.…”

The ability of a submaximal cycle ergometer test to detect longitudinal changes in VO2max

“…VO 2 max is the highest possible rate of oxygen consumption during a physically intense whole-body activity, and an important factor for many types of physical performance. It has also been linked to several health-related outcomes, with a low capacity being strongly associated with increased risk for cardiovascular disease, the metabolic syndrome, a negative influence on cognitive function, and more recently, severe Covid-19 [ 1 – 5 ]. In a scientific statement from the American Heart Association, the inclusion of measurement of VO 2 max in clinical practice is urged for to provide the clinicians with vital possibilities to improve patient risk management and health [ 6 ].…”