Effectiveness of Physical Activity Interventions in Sedentary People during COVID-19 Lockdown: A Systematic Review of Randomized Controlled Trials

By inergency On Feb 5, 2024

1. Introduction

The recent COVID-19 pandemic has changed the lifestyle of practically all populations in the world. In order to stop the contagion, governments imposed public health measures consisting of the restriction of usual activities, such as the closure of businesses and the prohibition of social gatherings and mass events [1]. These measures certainly helped to mitigate the spread of the virus and reduced the burden during the pandemic [2], but they also significantly limited opportunities to engage in physical activity and exercise since parks, gyms, and sports clubs could not be accessed during the restrictions [3]. At the same time, restraint measures encouraged an escalation in sedentary behavior; for example, worldwide, there was an increase in the time spent sitting or in front of a screen, which was already high before the pandemic at all ages [4].

The accrued evidence clearly shows how physical activity and exercise can effectively contribute to health maintenance and the prevention of cardiovascular, metabolic, neurodegenerative, and musculoskeletal diseases, today being considered a measure of paramount public health relevance [5,6,7]. On the other hand, there is also cumulative evidence of the negative consequences of a sedentary lifestyle [4,8,9]. In fact, it has been reported that physical inactivity leads to an approximately 9% increase in premature mortality [4,8] and a rise in healthcare costs of up to 4.6% [10]. Physical inactivity is a major risk factor for several conditions [4,11]. The 2018 Physical Activity Guidelines Advisory Committee Scientific Report concluded that high amounts of sedentary behavior increase the risk of all-cause and cardiovascular disease mortality, as well as of incident cardiovascular disease and type 2 diabetes, with strong evidence. There was moderate evidence indicating that sedentary behavior is associated with incident endometrial, colon, and lung cancer and limited evidence suggesting that sedentary behavior is associated with cancer mortality and weight status. In addition, there was strong evidence indicating that the hazardous effects of sedentary behavior are even more pronounced in physically inactive people [11]. A recent study including 65,361 adults showed a 34% reduced risk of hospitalization, 41% reduced risk of ICU admission, 45% lower need for mechanical ventilation, and 42% reduced risk of mortality in people with a high level of physical activity when compared to those with low levels [12].

Considering the crucial role that physical activity and exercise play in health status at the population level, various investigations have been performed to evaluate the consequences of the restrictions on public life in terms of people’s behavior. A systematic review of 66 studies including a total of 86,981 participants published in 2021 found that the majority of studies reported decreases in physical activity and increases in sedentary behaviors during their respective lockdowns across several populations, including children and patients with a variety of medical conditions [13]. These results were strongly confirmed by a recent quantitative analysis based on a systematic review and meta-analysis of 173 trials with over 320,000 participants [14]. Compared to the pre-pandemic data, total physical activity and walking decreased by 35% and 48%, respectively, taking into account all levels of physical activity from light to vigorous in similar proportions, with a parallel increase in sedentary behavior. There was no influence of sex, age, body mass index, or health status [14].

Consequently, there is no doubt about the foremost importance of identifying strategies to maintain or even improve physical activity during restrictions on social life. A number of methods have been proposed in periods of lockdown, including tele-coaching and other digital techniques, which could be used to promote and advise physical activity without having contact with people.

Based on this background, with the present systematic review, we aimed to evaluate whether the interventions reported in randomized controlled trials (RCTs) were effective in terms of the effects of physical activity (tele-coaching) during the COVID-19 lockdown on people with sedentary behavior.

2. Materials and Methods

This systematic review adhered to the PRISMA statement [15] and followed a pre-planned but unpublished protocol.

2.1. Data Sources and Searches

Six investigators (S.C., C.C., A.D.A., A.G., S.M.L., F.B.) conducted a literature search using PubMed/Medline and Web of Science from database inception until 1 April 2023.

In PubMed, the following search strategy was used: (Sedentary Behavior* OR Sedentary Lifestyle OR Physical Inactivity OR Lack of Physical Activity OR Sedentary Time) AND (“covid 19” [MeSH Terms] OR “covid 19” [All Fields] OR “covid19” [All Fields] OR “covid 19” [All Fields] OR “covid 19” [MeSH Terms] OR “sars cov 2” [All Fields] OR “sars cov 2” [MeSH Terms] OR “severe acute respiratory syndrome coronavirus 2” [All Fields] OR “ncov” [All Fields] OR “2019 ncov” [All Fields] OR “coronavirus” [MeSH Terms] OR “coronavirus” [All Fields] OR “cov” [All Fields])”. Any inconsistencies were resolved by consensus with a senior author (L.J.D.).

2.2. Study Selection

We used the following PICO question for the study inclusion: in people with sedentary behavior during the COVID-19 pandemic social restrictions (P), compared with a control group (C), what was the effect of any physical activity intervention (I) in increasing the physical activity level (O) based on the evidence derived from intervention studies with a control group (S)?

Studies were excluded if they (i) did not include humans; (ii) did not have sufficient information regarding interventions or regarding outcomes of interest; (iii) did not have a control group. We used the Rayyan systematic review platform (https://www.rayyan.ai/, 1 April 2023) for the selection of the studies to include based on the title/abstract information.

2.3. Data Extraction

The six independent investigators cited before (S.C., C.C., A.D.A., A.G., S.M.L., F.B.), in couples, extracted key data from the included articles into a standardized Excel spread sheet, with two senior authors (N.V. and M.B.) checking the data. For each article, we extracted data on the author names, year of publication, country, sample size, demographics, setting/population, type of study and type of intervention, and follow-up (weeks). Concerning physical activity, we extracted data regarding the baseline presence of physical inactivity/sedentary behavior, the instruments used for the defining physical activity levels in the studies, and the tools used to increase the physical activity levels.

2.4. Outcomes

The outcome of interest in our systematic review was the physical activity level, defined as any bodily movement produced by skeletal muscles that results in energy expenditure, as defined by the World Health Organization (World Health Organization 2019), after a follow-up period with a specific training intervention compared to a control group not undertaking any specific training. The physical activity level was recorded according to the data originally reported in the studies, i.e., using questionnaires or objective tools, such as accelerometers.

2.5. Quality Assessment

The quality/risk of bias assessment was made using the tool suggested by JBI [16]. This tool is based on 13 different questions regarding the methodological aspects of an intervention study. In detail:

Study Design Consideration: JBI provides specific tools tailored to different study designs. For intervention studies, common designs include RCTs, non-randomized controlled trials, and quasi-experimental designs.
Structured Criteria: Each tool consists of a set of structured criteria relevant to the specific study design. These criteria guide the appraiser in evaluating various aspects of the study methodology, including the study population, intervention, comparison groups, outcomes, and statistical analysis.
Validity and Reliability: The tools assess the validity and reliability of the included studies. This involves examining the appropriateness of the study design for addressing the research question, ensuring the proper randomization and allocation concealment in RCTs, and evaluating the potential for bias.
Outcome Measurement: Evaluation of the tools involves scrutinizing the clarity and appropriateness of the outcome measures, whether objective or subjective. It considers whether the outcomes align with the research question and whether they are measured consistently across groups.
Data Analysis: The tools assess the statistical methods used in data analysis, including whether appropriate statistical tests were applied, whether the analysis accounts for potential confounding variables, and whether the results are reported clearly.

2.6. Data Synthesis and Analysis

The data are reported descriptively since extremely heterogeneous definitions of physical activity or tools for improving this aspect were used in the studies. We therefore reported the main findings of the studies included, indicating whether the associations reported were statistically significant at a p-value < 0.05.

4. Discussion

In the present systematic review, we aimed to appraise the effects of interventions on physical activity (such as tele-exercise, tele-coaching) among people with sedentary behavior during the COVID-19 lockdown. Starting from over 2400 records in the original literature search and after reviewing them according to the latest PRISMA recommendations, 11 studies with a total of 1770 participants were available and were included in the systematic review. We found that most of the studies examined reported the beneficial effects of the proposed interventions in improving the level of physical activity, reducing the sedentary time, and positively contributing to the psychological well-being of the participants.

Of the 11 RCTs meeting the inclusion criteria and included in the systematic review, 8 (73%) [17,18,19,22,23,24,25,26] showed strongly positive results even considering that they referred to different age groups, from children to older adults, and to people from different countries and performed different modalities of coaching programs. Only three studies [20,21,27] showed no benefit or some benefit that was not completely effective. First, Ferreira et al. [20] reported that the intervention in adolescents consisting of sending educational information on physical activities according to the Brazilian guidelines using illustrated messages through WhatsApp was not effective in increasing physical activity and reducing the time spent on sedentary behavior. In this study, participants did not receive specific coaching but only illustrated information. Much of the efforts in health promotion to the public are based on the idea that information is powerful, e.g., if the person knows that there are negative consequences of not exercising, they will surely take action and exercise. However, information alone is not enough to change behavior. The fundamental principles of health behavior and psychological strategies must be considered, which truly help people adhere to healthy programs that are beneficial to them [28]. Self-monitoring strategies such as step-counting by means of the use of accelerometers, smartphone applications, or other body-tracking devices can help improve adherence to and the persistence of physical activity and exercise performance. Indeed, these types of strategies have been shown to be effective in terms of short- and long-term increases in physical activity [29]. Second, Granet et al. [21] reported the beneficial effects of a web-based physical activity intervention in improving functional capacities and the physical activity level during the COVID-19 lockdown, with a slightly higher adherence and lower drop-out rate in the live interactive group compared to the group following a recorded video, suggesting the preference of the first option instead of the recorded modality. Third, Teuber et al. [27] used a digital nudging intervention of daily digital motivational prompts among university students who studied at home most of the time. The intervention did not show any significant effect on their likelihood to participate in physical activity breaks. However, the longer a student studied at home during the day, the more their likelihood of taking part in a physical activity break increased. The authors concluded that relying solely on digital nudging is not enough to encourage interrupting sedentary behavior. As in the study by Ferreira et al. mentioned above, programs that are not proactive, as were the interventions in the other eight studies showed to be strongly effective [17,18,19,22,23,24,25,26], are not sufficient to modify behaviors and significantly increase physical activity during social restriction measures.

According to the 2020 WHO Guidelines for Physical Activity and Sedentary Behavior [4], extensive and growing cumulative evidence reinforces the universal recommendation of “moving more and sitting less” as a fundamental measure for the prevention and treatment of numerous diseases. Unfortunately, inactivity and sedentary lifestyles have grown and continue to rise in modern societies. Despite the benefit of improvements in living conditions, new technologies induce people to move around less, posing a serious public health problem worldwide. In the USA alone, the cost of not complying with the recommended level of physical activity amounts to about 117 billion USD in healthcare costs per year and nearly 10% of related premature deaths [30]. A sedentary lifestyle has been linked to a number of adverse health effects, including all-cause and cardiovascular mortality, cardiovascular disease, incident type 2 diabetes, and some types of cancer [31]. In older adults, it is essential to maintain autonomy by performing physical activity adapted to each person’s conditions. Various studies have shown the positive associations of a higher level of physical activity and less sedentary lifestyle with maintenance of the ability to perform activities of daily living [32,33], as well as with better muscular strength and power [34,35] and cognitive performance [6,7,36]. A recent meta-analysis including 17 cohort studies and over 200,000 participants followed for a median of 7.1 years reported a significant inverse association between daily step count and all-cause and cardiovascular mortality [37]; a 1000-step increment was associated with a 15% decreased risk of all-cause mortality, while a 500-step increment was associated with a 7% decreased risk of cardiovascular mortality.

Just as the crucial role that physical activity plays in maintaining health is universally accepted, compelling evidence supports its association with the prevention and improvement of several chronic non-communicable diseases [4,8,30,38]. Even short periods of inactivity can significantly increase adverse health effects. Older adults subjected to bed rest for 10 days experienced about a three-fold greater loss in lean leg muscle mass compared with a cohort of younger adults confined to bed for 28 days [39,40,41], resulting in substantial lower extremity strength, power, and aerobic capacity [42]. Likewise, a period as short as five days of bed rest caused arterial stiffness, endothelial dysfunction, and increased diastolic blood pressure in healthy adults [43], while two weeks of step reduction decreased their insulin sensitivity and cardiorespiratory fitness in parallel with an increase in body fat and liver fat [44]. These modifications are mostly reversible in young people, as opposed to what happens in older adults, in whom they can lead to chronic immobility.

A comprehensive review of various databases aiming to describe the deleterious effects of prolonged bed rest on the body systems of older adults found 1639 articles on the subject. After the application of the established criteria, 9 articles remained, and 20 were added to maintain the citations of the primary sources, giving a total of 29 articles. The authors found that most of the articles confirmed that the immobility associated with prolonged bed rest is detrimental to the health of older adults, as it affects several systems, such as the cardiovascular, pulmonary, gastrointestinal, musculoskeletal, and urinary systems, which may lead to the onset of diseases in addition to those that led to the bed rest [45]. Moreover, a recent systematic review and meta-analysis aiming to evaluate the magnitude of effects on muscle mass, strength, power, and functional capacity changes as well as the mechanisms, molecules, and pathways involved in muscle decay during bedrest included a total of 25 studies in the qualitative synthesis and 17 studies in the meta-analysis. Overall, the total lean body mass decreased by 1.5 kg, while there was no relationship between the bed rest duration and outcomes. The meta-analysis showed that bed rest produced large statistically significant effects on muscle power. The knee extension power was decreased by 14.65 N/s, and meta-regression showed a significant relationship between the bed rest duration and knee extension power. Moderate, statistically significant effects were observed after bed rest intervention in terms leg muscle mass in both old and young adults with a higher magnitude of change in older than younger adults [46]. The negative effects of bed rest are not confined to the musculoskeletal system but may extend to other organs. For example, only a short period of bed rest is needed to observe a deterioration in cardiovascular function and structure, with a similar impact to spaceflight [47]. In as little as seven days of bed rest, the left ventricular diameter is reduced, and the isovolumetric relaxation time is prolonged [48].

In addition to its prime impact on physical functions, the effects of physical inactivity on psychological well-being are well documented. This was particularly evident during the COVID-19 pandemic, with restriction measures leading to a significant increase in the risks of depression and anxiety [49]. Before the pandemic, it had already been shown that leisure time physical activity (LTPA) was associated with well-being [50,51]. Using data from the 1970 British Cohort Study (n = 5197), a higher LTPA intensity at baseline was associated with lower psychological distress. The baseline LTPA frequency and intensity were associated with a higher psychological well-being [50]. A recent meta-analysis including 157 studies with 190 independent samples and 524,770 participants found that the majority of effects (82.24%) were positive, indicating that participants who exercise physically had higher well-being scores compared to those who do not exercise. The relation between physical activity and subjective well-being was stronger in intervention studies with structured physical activity programs compared to correlational and quasi-experimental studies. Overall, the results of the meta-analysis showed the small but significant effect of physical activity on subjective well-being, which was independent of the prior fitness level of the participants and of the characteristics of the physical activity intervention [51].

The clear positive association between physical activity and mental well-being during the pandemic was reported in a systematic review by Li et al. [52]. Based on the results of 23 studies, the authors found that regular physical activity, high-intensity physical activity, and a physical activity duration of 30–60 min or more per day were associated with a lower risk of anxiety, depression, and negative emotions. Contrariwise, residents with no exercise or with physical inactivity were more likely to have anxiety, depression, sleep disturbances, and lower subjective well-being [52]. For all these reasons, it is crucial to identify methods to maintain or even increase physical activity during forced social restrictions. As shown in the present systematic review, diverse strategies of tele-coaching have been proven effective for this purpose.

The strengths of the present systematic review comprise the possibility of identifying quality RCTs among the numerous publications proposed on the subject during the pandemic period, which allowed us to verify the effectiveness of the remote interventions in improving physical activity, which may be applied even outside the pandemic in circumstances that prevent in-person programs. Another strength is the possibility of updating the available information in the medical literature on a relevant public health burden such as fighting against a sedentary lifestyle. However, the findings of the present systematic review should be interpreted with reference to its limitations. First, only 11 RCTs were identified as suitable for the analyses according to the PRISMA recommendations. Although this may seem a small number, these studies were of discrete quality according to JBI, and the number of participants was adequate (1770 participants, half in the intervention groups and half in the control groups). Another limitation is that the studies used different methods for the interventions, and there was not enough information to allow the performance of a meta-analysis. Finally, the data on some important determinants of the response to physical activity, such as ethnicity, were poorly reported, not allowing any speculation about this point. Likewise, given the heterogeneity of the information available, it is not possible to quantify the degree of improvement that physical activity can produce in sedentary people.