Cardiorespiratory Fitness and Risk of COVID-19 Infection, Mortality

Pavankumar Kamat


May 18, 2021


  • Estimated cardiorespiratory fitness (eCRF) had no significant association with the risk of testing positive for COVID-19.

  • However, people with moderate or higher eCRF had a significantly lower risk of dying from COVID-19.

Why this matters

  • Physical activity is a modifiable behaviour that positively affects CRF and an effective intervention to reduce the negative health effects of COVID-19 lockdowns.

  • The findings provide additional support to these recommendations and suggest that prior physical activity may offer protection against dying from COVID-19.

Study design

  • A prospective cohort study of 2690 participants from the UK Biobank who were tested for COVID-19.

  • CRF was estimated using maximum oxygen consumption (VO2 max) and classified as low (<20th percentile), moderate (20th to <80th percentile) and high (≥80th percentile) within sex and 10-year age groups.

  • Funding: None.

Key results

  • Of 2690 participants, 346 tested positive for COVID-19.

  • No difference was seen in the mean estimated VO2 max between those who were tested for COVID-19 (27.3±5.5 mL/kg/min) and those who tested positive for COVID-19 (27.3±5.4 mL/kg/min).

  • Moderate (adjusted risk ratio [aRR], 0.93; 95% CI, 0.72-1.21) and high eCRF (aRR, 0.77; 95% CI, 0.52-1.15) vs low eCRF were not associated with an increased risk of testing positive for COVID-19.

  • Conversely, low eCRF vs moderate and high eCRF was associated with >2 times higher risk of dying from COVID-19 (aRR, 2.34; 95% CI, 1.35-4.05).

  • Compared with low eCRF, the risk of dying from COVID-19 increased with (aRR; 95% CI):

    • moderate eCRF (0.43; 0.25-0.75); and

    • high eCRF (0.37; 0.16-0.85).


  • Approximate 10-year lag between baseline measurements and COVID-19 testing.


Christensen RAG, Arneja J, St Cyr K, Sturrock SL, Brooks JD. The association of estimated cardiorespiratory fitness with COVID-19 incidence and mortality: A cohort study. PLoS One. 2021;16(5):e0250508. doi: 10.1371/journal.pone.0250508. PMID: 33951071.  View full text

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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