How does obesity affect sleep duration, and what is obesity's relationship with coronavirus disease 2019 (COVID-19)?

Updated: Jun 09, 2021
  • Author: Osama Hamdy, MD, PhD; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
  • Print

Sleep duration of less than 5 hours or more than 8 hours was associated with increased visceral and subcutaneous body fat, in a study of young African Americans and Hispanic Americans. [30] This association relates mostly to decreased leptin hormone and increased ghrelin hormone levels. [31]


The Centers for Disease Control and Prevention (CDC) includes obesity in the list of conditions that increase the likelihood of severe illness in persons with COVID-19. [32]

A report released in March 2021 by the World Obesity Federation stated that the mortality risk from coronavirus disease 2019 (COVID-19) is about 10 times higher in countries where more than 50% of the adult population is classified as overweight. Of deaths worldwide from COVID-19 reported by the end of February 2021, almost 90% were found to have occurred in countries where the majority of adults were overweight. [33, 34]

A study reported that out of 178 adult patients hospitalized with COVID-19, at least one underlying condition was found in 89.3%, the most common being hypertension (49.7%), obesity (48.3%), chronic lung disease (34.6%), diabetes mellitus (28.3%), and cardiovascular disease (27.8%). Moreover, obesity was the most prevalent underlying condition among patients aged 18-64 years. [35]

In addition, a report by Lighter et al, based on data from a large academic hospital system in New York City, indicated that in persons under age 60 years, obesity increases the risk of hospitalization for COVID-19 two-fold, with such patients also being more likely to require intensive care. [36, 37]

A study by Kass et al indicated that among patients with COVID-19 admitted to the intensive care unit (ICU), there is a greater tendency for younger individuals to be obese, with age inversely correlated with BMI. [38, 39]

A relationship between obesity and progression to severe COVID-19 status was also seen in studies by Cai et al and Gao et al, with the Cai study indicating that the odds ratio (OR) of persons with obesity progressing to severe disease is 3.4, and the Gao study finding the progression to severe or critical COVID-19 status to be threefold greater in patients with obesity. [40, 41, 42]

A study from the CDC of adults with COVID-19 reported that BMI has a nonlinear (J-shaped) relationship with COVID-19 severity. With regard to ICU admission, the risk was indicated to be 6% greater in patients with a BMI of 40-44.9 kg/m2, rising to 16% greater in association with a BMI of 45 kg/m2 or higher. The mortality risk in adults with obesity was 8% greater in patients with a BMI of 30-34.9 kg/m2, rising to 61% higher with a BMI of 45 kg/m2 or more. The results also indicated that patients under age 65 years with obesity are at particular risk for hospitalization and death due to COVID-19. In addition, the study found that people who are underweight also have a greater risk for hospital admission due to COVID-19, with the likelihood being 20% higher in persons with a BMI below 18.5 kg/m2, compared with individuals with a healthy BMI. [43, 44]

A study by Gao et al indicated that there is a linear increase in the risk for severe outcomes in COVID-19 as an individual’s BMI rises past 23 kg/m2, with the risk turning upward even in light of a small rise in body mass. Moreover, this phenomenon appears to be independent, being unassociated with the presence of diabetes and other diseases related to obesity. Additionally, similar to the above CDC study, the investigators found the relationship between body mass and hospitalization from COVID-19 to be J-shaped, observing that patients with BMIs at or below 20 kg/m2 were also at increased risk. It was determined as well that for persons in the study between age 20 and 39 years, the risk of COVID-19–related hospitalization for increases in BMI above 23 kg/m2 was greater than for patients aged 80-100 years, while the risk of hospitalization and death in association with increased BMI was higher for Black persons than for White ones. [45, 46]

A study from England, by Szatmary et al, suggested that overweight or obese young men with COVID-19 may be at particular risk for developing pancreatitis. [47, 48]

A study by Guerson-Gil et al indicated that in hospitalized adult patients with COVID-19 and obesity, men have a significantly greater likelihood of in-hospital death than do women. The investigators found, for example, that in patients with a BMI of 35-39.9 kg/m2, the odds ratios (ORs) for mortality in the study were 1.0 and 1.99 for women and men, respectively, while for those with a BMI of 40 kg/m2 or above, the ORs were 1.72 and 2.26, respectively. [49, 50]

An international study reported that after older age and male sex, obesity is the greatest risk factor for severe pneumonia, that is, pneumonia requiring invasive mechanical ventilation, in ICU patients with COVID-19. BMI was found to have a linear correlation with the need for such ventilation, with obesity’s highest impact seen in women under age 50 years. [51]

Research also indicates that patients with obesity are more likely to suffer long-haul COVID-19 (ie, long-term complications associated with COVID-19). A study by Aminian et al looked at patients who required no intensive care unit (ICU) admission during the acute phase of COVID-19, following up a median 8 months after the initial 30-day period subsequent to a positive test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Persons with moderate or severe obesity had a 28% and 30% greater risk of hospital admission, respectively, than did patients with a normal BMI. In addition, the need for diagnostic tests to evaluate for various medical conditions (including tests of the heart, lung, and kidney and for gastrointestinal or hormonal symptoms, blood disorders, and mental health problems) was increased by 25% and 39%, respectively. [52, 53]

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!