Sarcopenia during COVID-19 lockdown restrictions: long-term health effects of short-term muscle loss

Abstract

The COVID-19 pandemic is an extraordinary global emergency that has led to the implementation of unprecedented measures in order to stem the spread of the infection. Internationally, governments are enforcing measures such as travel bans, quarantine, isolation, and social distancing leading to an extended period of time at home. This has resulted in reductions in physical activity and changes in dietary intakes that have the potential to accelerate sarcopenia, a deterioration of muscle mass and function (more likely in older populations), as well as increases in body fat. These changes in body composition are associated with a number of chronic, lifestyle diseases including cardiovascular disease (CVD), diabetes, osteoporosis, frailty, cognitive decline, and depression. Furthermore, CVD, diabetes, and elevated body fat are associated with greater risk of COVID-19 infection and more severe symptomology, underscoring the importance of avoiding the development of such morbidities. Here we review mechanisms of sarcopenia and their relation to the current data on the effects of COVID-19 confinement on physical activity, dietary habits, sleep, and stress as well as extended bed rest due to COVID-19 hospitalization. The potential of these factors to lead to an increased likelihood of muscle loss and chronic disease will be discussed. By offering a number of home-based strategies including resistance exercise, higher protein intakes and supplementation, we can potentially guide public health authorities to avoid a lifestyle disease and rehabilitation crisis post-COVID-19. Such strategies may also serve as useful preventative measures for reducing the likelihood of sarcopenia in general and in the event of future periods of isolation.

Keywords: Appetite regulation; COVID-19; Inflammation; Obesity; Physical activity; Sarcopenia.

Fig. 1

Potential model of age-associated muscle loss (sarcopenia) exacerbated by periods of extended bed rest/hospitalization due to acute illness or injury (catabolic crises). Adapted from English and Paddon-Jones (2010) [30]

Fig. 2

Composition of changes in body weight during calorie restriction under normal and restricted sleep conditions. Under conditions of restricted sleep (5.5 h), greater weight was lost as fat-free mass (including muscle) and less body fat was lost, compared to conditions of sufficient sleep (8.5 h). Adapted from Nedeltcheva et al. (2010) [73]

Fig. 3

Summary of potential effects of government restrictions on lifestyle behaviors and the mechanisms by which they can lead to reduced muscle protein synthesis and increased muscle protein breakdown resulting in muscle loss. The development of sarcopenia, or in the presence of caloric excess, sarcopenic obesity, is associated with a significantly increased risk of multiple comorbidities, some of which may also increase the risk of COVID-19 infection and severity. COVID-19 severe acute respiratory syndrome coronavirus 2, mTORc1 mammalian target of rapamycin complex 1, IL-6 interleukin-6, TNF-α tumor necrosis factor alpha, CRP C-reactive protein

Fig. 4

Summary of evidence-based resistance exercise variables reported to improve muscle size in older adults. These figures were calculated using data from a meta-regression of 25 randomized controlled trials. As many variations of training protocols are feasible for muscle gain, this collection of variables should be considered guidelines only and not as a defined training program. Adapted from Borde et al. (2015) [290]

Fig. 5

A summary of the physical activity, dietary, and supplement countermeasures that may be useful for preventing the loss of muscle mass and function in both younger and older adults. The inclusion of telehealth services offering regular contact, guidance, and support to such countermeasures may result in greater adherence and positive outcomes