Changes in Physical Activity and Cognitive Function of the Elderly Due to COVID-19 in South Korean
Article information
Abstract
PURPOSE
This study aimed to ascertain whether there were changes in the physical activity and cognitive function of older adults before and during the pandemic.
METHODS
We recruited 547 older individuals (277 men, 270 women). All participants were assessed (body composition, waist circumference, blood pressure, glucose, cognitive function, and physical activity) in 2019, before the coronavirus disease 2019 (COVID-19) pandemic was declared, and again in 2021 during the pandemic.
RESULTS
One-way analysis of variance (ANOVA) showed that SBP (p=.044), VPA (p<.001), MPA (p<.001), MVPA (p<.001), and cognitive function (p=.030) were significantly different among the older males group. One-way ANOVA indicated that weight (p=.045), SBP (p=.030), VPA (p<.001), MPA (p<.001), MVPA (p<.001), and cognitive function (p=.002) significantly differed among the older females group.
CONCLUSIONS
Social distancing and isolation contributed to a decline in physical activity and cognitive function in both older males and females in 2021, during the COVID-19 pandemic, compared to 2019, the year before the pandemic.
INTRODUCTION
The world is coping with the health, social, and economic consequences of the COVID-19 pandemic, which has lasted more than two years [1]. One of the strongest points of consensus around COVID-19 is that the elderly comprises the most vulnerable demographic. Moreover, because the elderly has been shown systematically to respond worse in terms of their willingness to self-isolate and quarantine, governments must revisit their approach to minimize the number of COVID-related deaths [2].
Patients with severe cognitive impairment due to Alzheimer's and related dementias constitute one of the groups most at risk for negative outcomes during quarantine. Furthermore, their decline in cognitive function and the inevitable impact of pathology on quality of life significantly impacts family and informal caregivers [3]. Among 435 nursing home residents, 190 (43.9%) tested positive for COVID-19, and their cognitive status deteriorated by 22% and 25.9% according to the global dete-rioration scale and Lobo's Mini-Examen Cognoscitivo, respectively [4]. After 12 months of follow-up data on the elderly (aged 70 and older), an association was observed between worsening cognitive function and experience with COVID-19 (-1.460; CI95%: −2.710 to −0.211) [5].
Moreover, in evaluating 203 frail hypertensive elderly during the COVID-19 pandemic, a significant correlation was found between cognitive assessment scores and gait speed tests (r: 0.495; p <.001); a significant association with age, diabetes, chronic obstructive pulmonary disease, and gait speed tests were also observed [6]. A one-year follow-up assessment of 29 physically active elderly females during the pandemic-induced lockdown showed significant increases in weight and body mass index after one year, resulting in 13.8% to 27.6% muscle loss [7]. This may suggest that physical inactivity among the elderly during the pandemic worsened both cognitive and physical function.
During COVID-19, restricted activity had a substantial physical and mental impact on elderly. This was a common phenomenon, not only in South Korea but also worldwide. However, in South Korea, social distancing and quarantine periods were stronger than in any other country. Therefore, this study seeks to ascertain whether there were changes in physical activity and cognitive function of the elderly before and during the pandemic.
METHODS
1. Participants
This study recruited a total of 547 elderly (277 males and 270 females). All participants were 65 years of age or older and were specifically recruited from N-Hospital (Incheon, South Korea) from January 2019 to December 2021 (two visits were made in 2019, one before the pandemic, and the other in 2021, during the pandemic). The dataset was drawn from a retrospective cohort based on N-Hospital Medical Informatics Data (NIHMID), and separate patient recruitment procedures were not carried out. Because the data were de-identified, subjects’ informed consent was not applicable. In the NIHMID, de-identified join keys replacing personal identifiers are used to secure ethical clearance. Therefore, the researcher cannot receive informed consent from individual patients for the use of personal information. However, using NIHMID for research purposes requires approval from the institutional review board. This study was approved by the N-Hospital Data Review Board (N-Hos-pital-2022-001).
The characteristics of the participants are shown in Table 1.
The characteristics of the participants at baseline
2. Cognitive function
As mentioned in the previous section, all participants were assessed for cognitive function using the Korean Dementia Screening Questionnaire Cognition (KDSQ-C) [8]. The KDSQ-C is self-administered and consists of 15 cognitive dysfunction items, each of which is rated on a three-point scale: 0 (no), 1 (sometimes/occasional), and 2 (often/frequent). The KDSQ-C is not influenced by age or educational level and has previously resulted in scores of 0.79 f or sensitivity and 0.80-0.86 for specificity among people with dementia [9,10]. According to a baseline KDSQ-C cutoff score of 6 points, participants were divided into two groups, including the cognitive impairment group (scores ≥6 points) and normal group (scores <6 points).
3. Physical activity amount
This study employed the computerized Korean version of the IPAQ, and is entirely based on the long, self-administered, common week-long IPAQ found in the IPAQ manual of operation. The 7-item IPAQ identifies the total number of minutes over the previous seven days that were spent on moderate-to-vigorous physical activity (MVPA), walking, and inactivity [11]. It is designed specifically to collect information on the durations of time (i.e., the number of sessions and average timeframe per session) spent walking, in moderate-intensity physical activity (MPA), in vigorous intensity physical activity (VPA), and inactivity (i.e., sitting on weekdays and weekends). Questions regarding participation in moderate and vigorous physical activities were supplemented by concrete examples of commonly performed behaviors. Data obtained via the questionnaires were then summed up for each item (i.e., vigorous intensity, moderate intensity, and walking) to estimate the total time spent in physical activity on a weekly basis.
Based on the self-reported time spent in MVPA, participants were categorized as either sufficiently or insufficiently active. These classifications were done according to guidelines set forth by the American College of Sports Medicine (ACSM)/Centers for Disease Control and Prevention (CDC) [12]. The stated recommendations were that individuals should accumulate at least 150 minutes of moderate-intensity activity per week.
4. Measurement of anthropometric and glucose
The participant's measured anthropometric variables included body mass, height, and waist circumference (WC). Body mass and height were measured to the nearest 0.1 kg and 0.1 cm, respectively, using a body composition analyzer (Inbody 720, Body Composition Analyzer; Bio-space, Seoul, Korea). Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. WC was determined using a steel measuring tape, with figures recorded midway between the lowest rib and the iliac crest in a horizontal plane.
Blood pressure (systolic blood pressure; SBP, diastolic blood pressure; DBP) was assessed three to four times after subjects had been resting quietly in a seated position for a minimum of 10 minutes.
Fasting venous blood samples were collected from all participants. Fasting was maintained for nine hours, and then blood samples were collected on the following day. Participants were instructed to obtain sufficient sleep and refrain from radical movements as much as possible. Samples were immediately centrifuged at 3,500×g at 4°C for 10 minutes and analyzed within 24 hours. Serum levels of glucose was evaluated by biochemical automatic analyzer using commercial kits (Hitachi 7180, Tokyo, Japan) according to the manufacturer's protocol.
5. Statistical Analysis
All results are reported as the mean±standard deviation, and all data were analyzed using SPSS version 29.0 (SPSS Inc., Chicago, IL, USA). Additionally, means and standard deviations were computed for all variables. The participants’ characteristics (height, weight, body mass index, waist circumference, systolic and diastolic blood pressure), glucose and physical activity amount (moderate, vigorous, and moderate-to-vigorous) were further evaluated to ascertain whether there were significant differences between the pre- and post-pandemic groups using a paired sample t-test. Additionally, participant's characteristics (height, weight, body mass index, waist circumference, systolic and diastolic blood pressure), glucose and physical activity amount (moderate, vigorous, and moderate-to-vigorous) were further assessed to determine if there were any s ignificant differences between the groups using a one-way ANO-VA. The group consisting of individuals who met the recommended MVPA levels (150 minutes per week) was set as the reference. A post-hoc analysis (Bonferroni) was used to compare specific differentiations in cases of significance, which was statistically accepted at the 0.05 level.
RESULTS
1. Change before and during the pandemic
Table 2 presents the changes in participants’ height, weight, BMI, WC, blood pressure, glucose, and cognitive function.
Change of before and during the pandemic
A paired sample t-test detailed the data for height (p <.001), weight (p =.007), SBP (p <.001), glucose (p <.001) and cognitive function (p = .001) for both male and female participants. In the male cohort, there were significant differences in height (p <.001), weight (p <.001), BMI (p =.007), SBP (p =.002), glucose (p <.001), and cognitive function (p = .002). Among the female participants, there were substantial variations in height (p =.007), SBP (p =.001), and glucose (p =.004).
Fig. 1 details the changes in the amount of physical activity among participants.
Differences in the amount of physical activity before and during the pandemic. (A) Moderate physical activity. (B) Vigorous physical activity. (C) Moderate-to-vigorous physical activity (MVPA). * p-vaule was analyzed by a paired sample t-test; * p<.05, ** p<.01.
A paired sample t-test rendered data for the total amount of moderate physical activity (p <.05), vigorous physical activity (p <.05), and moderate-to-vigorous physical activity (p <.01) (for both male and female participants). For the male participants, there were considerable differences in moderate physical activity (p<.05), and moderate-to-vigorous physical activity (p <.05). In the female cohort, there was noticeable differences in vigorous physical activity (p <.05).
2. Changes in the elderly male participants according to the amount of physical activity
Table 3 presents the changes in height, weight, BMI, blood pressure, glucose, physical activity amount, and cognitive function in 2019 (before the pandemic) and 2021 (during the pandemic), based on a physical activity level of 150 min/week.
Changes in the male elderly according to the amount of physical activity
A one-way ANOVA showed that SBP (p =.044), VPA (p <.001), MPA (p <.001), MVPA (p <.001), and cognitive function (p =.030) were significantly different between the two groups. A post-hoc analysis using the Bonferroni test indicated that physical activity was significantly less in the <150 min/week group, and even among the ≥150 min/week cohort, physical activity decreased during the pandemic. Furthermore, the <150 min/week group had substantially worse cognitive function during the pandemic than the ≥150 min/week group before the pandemic.
3. Changes in the elderly female participants according to the amount of physical activity
Table 4 presents the changes in height, weight, BMI, blood pressure, glucose, physical activity amount, and cognitive function in the 2019 figures (before the pandemic) and the 2021 data (during the pandemic), based on a physical activity level of 150 min/week among the female elderly.
Changes in the female elderly according to the amount of physical activity
A one-way ANOVA showed that weight (p =.045), SBP (p =.030), VPA (p <.001), MPA (p <.001), MVPA (p <.001), and cognitive function (p = .002) were notably differed between the groups. A post-hoc analysis using the Bonferroni test indicated that physical activity was significantly less in the <150 min/week group, and even among the ≥150 min/week cohort, physical activity decreased during the pandemic. Furthermore, even ≥150 min/week of physical activity greatly increased SBP during the pandemic. Moreover, cognitive function was worse during the pandemic, with a significant decrease in the <150 min/week group.
DISCUSSION
This study found a significant decrease in physical activity and cognitive function in elderly males and females in 2021, the year with the greatest degree of pandemic-induced social isolation, compared to 2019, the year before the COVID-19 pandemic. Furthermore, even 150 minutes of moderate to vigorous physical activity per week was associated with significantly less physical activity and worse cognitive function during the pandemic.
Prevalence of depression, anxiety, and post-traumatic stress disorder remained similar during the four weeks of quarantine after COVID-19 infection, but severe depression and somatic symptoms worsened during the four weeks of quarantine [13]. During the COVID-19 pandemic, the prevalence of sufficient physical activity decreased significantly from 36.0% (95% CI, 35.9% to 36.1%) in 2017-2019 to 30.0% (95% CI, 29.8% to 30.2%) in 2020 and 29.7% (95% CI, 29.5% to 29.9%) in 2021 [14]. Analyzing data from a community health survey of 229,269 adults in South Korea, the study found that participants reported decreased physical activity (49.6%), increased unhealthy diet (17.0%), and decreased sleep duration (9.4%), which were significantly associated with adherence to social distancing and isolation, COVID-19 prevention guidelines [15]. Social support is important for the daily activities of elderly living in community settings, and a socially engaged lifestyle correlates with higher cognitive scores in both community and nursing home contexts; indeed, several studies provide evidence of a link between social support and cognitive function [16,17]. A cross-sectional analysis evaluating the association between social activity and cognitive function in the elderly in China found that participation in social activities was associated significantly with improved cognitive function; moreover, it identified that engaging in social activities positively affected cognitive function in the elderly [18]. A longitudinal study of Korean elderly found that joining social activities may help preserve cognitive function [19]. Individuals with expanded social networks had greater access to various forms of material resources or health-related information and contact with someone provided a greater sense of purpose and emotional validation, factors which might be direct neurohormonal benefits, thereby positively influencing health-related behaviors and protecting people from cognitive decline [20,21]. In this study, both the elderly's amount of physical activity and cognitive function declined during pandemic-related periods of social distancing and. In addition, there was an increase in systolic blood pressure and blood sugar, indicating adverse health effects. These changes differed for males and females, with elderly males showing a decrease in MPA and MVPA, while elderly females showed a decrease only in VPA. Both males and females displayed a decline in cognitive function, but only the former showed a significant decline. Previous studies have reported that considering gender differences is especially important given that females are more likely to engage in social activities and maintain intimate relationships and broader social networks [22,23]. Moreover, Evans et al.'s meta-analysis found that the effect sizes were small and statistically significant, with a slight advantage for female elderly, and much more heterogeneity for females than males [24]. In addition, the adjusted odds ratios for cognitive impairment were 2.16 (95% CI, 0.66-7.05) and 1.80 (95% CI, 0.98-3.32) reported by males and females, respectively, in the group with a conservative mindset toward gender-role stereotypes; this suggests the influence of such stereotypes held by females in Korean society [25]. Our results also indicated a decrease in cognitive function scores among the male and female elderly, but the change was substantial only for the males; this suggests that gender-role stereotypes may be a contributing factor, although not a substitute.
Many studies recommend at least 150 minutes of MVPA per week to improve the health of the elderly [26,27]. Specifically, physical activity improves cognition, particularly executive function and memory in mild cognitive impairment (MCI), independent functioning in MCI and dementia, and psychological health in dementia [28,29]. Hoffmann et al. reported that supervised moderate-to-high intensity exercise in patients with mild Alzheimer's reduced neuropsychiatric symptoms and cognitive preservation benefits [30]. Hsiao et al. demonstrated that those who participated in more than three hours of light physical activity (LPA) per day were less likely to develop cognitive impairment (odds ratio [OR]: 0.16; 95% CI: 0.03-0.80; p =.025), thus supporting the results that participating in over three hours of LPA daily may help maintain cognitive function in the elderly [31]. The study also used a cutoff of 150 minutes of physical activity per week to show changes before and during the pandemic. For both male and female elderly, MPA and VPA decreased during the pandemic compared, even at≥150 minutes of weekly physical activity. Furthermore, among the female elderly, cognitive function was noticeably reduced in the <150 min/week of physical activity group, compared to the ≥150 min/week cohort during the pandemic. In addition, we found two unusual findings. First, the amount of MPA changed among the male elderly, as did the VPA for the female elderly. Second, SBP increased for both the male and female elderly during the pandemic. Among the elderly female, light physical activity was positively associated with mental quality of life, after adjusting for moderate-to-vigorous physical activity [32]. A total of 7,854 males and 10,876 females over a 15-year period were examined for assessing the association between physical activity intensity and cardiovascular disease; this was done using a multistage randomized sampling method and it was found that MPA had no effect, but that VPA did have a significant protective role in male (OR=1.319 and 0.615), and that MPA and VPA had a strong protective effect in female (OR=0.593 and 0.537) [33]. The COVID-19 pandemic has contributed to more changes in female's traditional work experiences compared to male (e.g., reduced working hours, increased non-face-to-face remote work, and unemployment) that have contributed to decreased physical activity, with female reported experiencing significantly more generalized anxiety [34]. Anxiety and depressive symptoms may be associated with female's physical activity and mental health, suggesting that support for female may be needed following the COVID-19 pandemic [15]. The intensity of physical activity for males and females varies depending on the conditions, but it is clear that a minimum amount of physical activity positively impacts health. In the elderly, reduced physical activity might indicate a progression of increased SBP [35]. In fact, MPA and time spent in sedentary bouts for more than one hour were predictors of SBP; more MPA and less prolonged sedentary time were associated with a weaker systolic blood pressure response in adults [36]. In this study, changes in SBP were likely due to decreased physical activity resulting from pandemic conditions.
In addition to the insights and findings offered by this paper, there are some limitations. First, physical activity was measured by survey; thus, objective measurements of physical activity should be done in future studies. Second, although it has been made clear that minimal amounts and intensities of physical activity have health benefits, future studies should evaluate the effects of gender and intensity on cognitive function. In addition, participants were recruited from only one region. This is not representative of the entire country, and future studies should recruit from all regions of Korea. Finally, although the decrease in cognitive function and in physical activity were identified together, there are limitations in identifying cause and effect, which should be considered in future studies.
CONCLUSION
In conclusion, this study indicated that there was a decrease in physical activity and cognitive function in both elderly males and females in 2021, the year experiencing the greatest degree of pandemic-induced social isolation, compared to 2019, the year before the pandemic. Furthermore, even for those with ≥150 min/week of moderate-to-vigorous physical activity per week in 2019 were associated with significantly lower physical activity amount and cognitive function during the COVID-19 pandemic.
Social distancing and isolation resulting from the unprecedented global COVID-19 pandemic negatively impacted both physical activity and cognitive function in the elderly. In turn, this has significantly impacted the elderly's health. As such, important measures to improve their health are needed.
Notes
CONFLICT OF INTEREST
The authors declare that they have no competing interests.
AUTHOR CONTRIBUTIONS
Conceptualization: E Lee, ST Lim; Data curation: E Lee, ST Lim; Formal analysis: E Lee, ST Lim; Methodology: E Lee, ST Lim; Writing - original draft: E Lee, ST Lim.