The first objective of this study was to compare functional status, physical activity level, QoL, fatigue, among patients diagnosed with Long COVID and those who were infected with COVID-19 but did not develop symptoms compatible with the diagnosis of Long COVID.
Our results showed positive and highly significant correlations between the group diagnosed with long-term COVID and those who did not develop symptoms compatible with it, in terms of functional status, physical activity level, quality of life and fatigue. It was observed that participants diagnosed with Long COVID showed severe functional limitations in a much higher percentage than the group that did not develop symptoms compatible with this new condition. Likewise, their level of physical activity is low, and they experienced a deterioration compared to the previous state. Regarding QoL, our results revealed a greater deterioration in those patients diagnosed with Long COVID compared to the group that did not develop symptoms after infection, in which maintenance is observed.
Among people diagnosed with Long COVID, persistent symptoms can cause a variety of disorders, including dyspnea, fatigue, functional impairment, and cognitive sequelae.36. Understandably, these complications have significant clinical and practical implications for health and well-being37. This fact also raises important questions about the functional presentation and consequences of Long COVID, especially in women, who are the majority group, as can also be seen in our sample; and since they tend to have more age-related disability than men38. Similarly, despite not requiring hospitalization, people with COVID-19 infection may also be at risk of deterioration in physical, cognitive, and mental health39.
Furthermore, some studies support our results, finding a debilitating symptom profile in patients that reflects far-reaching consequences for health and well-being40. Prolonged periods of morbidity and reduced engagement in daily activities, sedentary behavior and consequent decline in quality of life were observed.41. It has also been established that long-term COVID affects the energy reserves of those suffering from it42.
One study found no association between duration of COVID infection and levels of physical activity and independence. However, it was observed that people with a longer duration of the disease could not return to their previous level of physical activity43. Other studies have also shown low levels of physical activity due to more sedentary behavior44.
According to our results, the study reported that more than half of the patients who developed Long COVID had a worse quality of life. These patients reported pain or discomfort, health problems, mobility problems, problems related to daily activities or self-care45. Other studies have also reported that Long COVID results in poor quality of life, possibly caused by post-traumatic stress syndrome.46. However, it is very likely that the consequences of COVID-19 alone or in combination can reduce QoL47. In contrast, Narayan Poudel et al.48 concluded that acute infection with COVID-19 has a greater impact on QoL than Long COVID.
On the other hand, taking into account the severity of fatigue, our results showed a significant worsening in those patients with long-term COVID, meeting CFS criteria in 92.4% of cases. Another study also found CFS in more than half of their sample, with significant fatigue burden at a median follow-up of 10 weeks6. This is of particular concern, given that it is recommended to return to work after a viral infection after 4 weeks to avoid deconditioning49. Fatigue after COVID, according to the literature, is found in 40% of people one year after the initial infection, and 1 in 4 meet the diagnostic criteria for CFS at that time6,13. Moreover, fatigue is not only extremely common in cases of prolonged COVID, but its severity and persistence can disrupt life50. Although it is currently unclear how to treat chronic fatigue in people with long-term COVID, pulmonary rehabilitation may be crucial in treating these individuals13.
As a second aim of this study, we aimed to determine whether functionality, level of physical activity and severity of fatigue are related to patients’ quality of life. Our results also show a very significant correlation of these analyzed variables with the patients’ quality of life. This implies that those patients in the sample with more severe functional limitations, lower levels of physical activity and greater severity of fatigue experienced a more pronounced reduction in their quality of life. However, despite the significant association, only the patients’ functional status was found to be a predictor of QoL.
As noted so far, one of the main characteristics of Long COVID is the disability caused by its symptoms, which can alter functionality to the point of incapacitating the patient in performing daily tasks.51. In Spain, it was found that more than 70% of patients diagnosed with Long COVID had limitations that prevented them from performing ADLs. This disability had a significant impact on their QoL52. Various exploratory analyzes are consistent with our results regarding the relationship between fatigue, decreased function or increased disability, and decreased quality of life53.
This highlights the need for QoL recovery, and exercise has been shown to significantly improve pain tolerance, mobility, optimization of physical function, and recovery of autonomy in ADLs. In addition, psychological improvements resulting from exercise could provide patients with a coping strategy to help them overcome a health challenge, directly affecting their quality of life10.
In this sense, both physical inactivity and sedentary behavior are independent risk factors for multiple adverse effects on health and reduced quality of life.54. Therefore, the establishment of rehabilitation programs to prevent secondary consequences of physical inactivity is a priority43.
The range of symptoms associated with Long COVID, as well as their severity, frequency and duration, present significant challenges for publishing precise recommendations on physical activity in these individuals42. One study found that after 8 weeks of physical rehabilitation, physical function and exercise capacity can improve, but functional status remains below the expected value for the patient’s age.50. In another study, it was found that after 6 weeks of pulmonary rehabilitation, the exercise capacity of patients with Long COVID significantly improved13.
Although some limitations were found in the study, further research is needed to determine the causality of the effects of Long COVID and its impact on daily life, as this was a cross-sectional study. The study was conducted in one Spanish autonomous community, which can be considered a limitation when extrapolating the results to the general population. Therefore, it would be necessary to expand the sample and expand the geographical area, including different urban and rural areas. There is a need for further research in this area, as few studies have been conducted on this topic. It is also worth noting that the type of survey used may lead to information bias as it is a self-administered survey.
In conclusion, our results showed highly significant correlations between the group that developed long COVID and those who did not have symptoms in terms of functional status, physical activity level, quality of life and fatigue. We found severe impairment of functional limitations, low levels of physical activity, significant deterioration of their quality of life and fatigue in patients diagnosed with Long COVID. Likewise, functionality, level of physical activity and severity of fatigue are also directly related to quality of life. Therefore, the worse the functional status, level of physical activity and fatigue, the worse their QoL. Although one of these variables was found to be a predictor of QoL, which is a person’s functional status.
The current findings highlight the urgent need to create specific strategies to address protracted COVID and patient support pathways that enable recovery of pre-COVID-19 quality of life55. According to our results, there is also a need to address this profound physical and quality-of-life impact through recommendations tailored to each individual’s clinical condition and multidisciplinary approaches through different healthcare professionals. Physical and cognitive rehabilitation is emphasized in this case in order to solve the deficiencies caused as a result of the COVID-19 infection.50.
The importance of continuing to conduct studies that delineate the correct path to recovery for patients with Long COVID is emphasized, highlighting the extent to which the chronic effects of Long COVID affect the health, well-being and QoL of the population. The increasing burden of rehabilitation emphasizes the need to develop effective interventions and multidisciplinary support pathways.