Effect of the COVID-19 pandemic on weight loss of Korean athletes: changes in athletes’ physical activity and eating behavior
Article information
Abstract
[Purpose]
This study aims to examine the physical activity and eating habits of elite athletes to identify changes in their weight and participation levels in competitions pre- and post-COVID-19, and to establish a database of the abovementioned factors for the post-COVID-19 period.
[Methods]
This study surveyed 913 elite adult athletes from 22 sports. They were divided into two groups: weight loss athletes’ group (WLG) and non-weight loss athletes’ group (NWLG). In addition to demographic factors, the questionnaire included questions about physical activity, sleep, and eating habits pre- and post-COVID-19 pandemic. The survey included 46 questions requiring short subjective answers. Statistical significance was set at p<0.05.
[Results]
In the post-COVID-19 pandemic period, physical activity and sitting decreased in athletes of both groups. The difference in the number of meals consumed by both groups varied, and the number of tournaments the athletes participated in decreased for all sports. The success or failure of weight loss is essential for maintaining athletes’ performance and health.
[Conclusion]
Coaches play an important role in investigating and managing the weight loss regimen of athletes during crisis situations like a pandemic. Additionally, athletes must find the best way to maintain their competencies to the standards set before COVID-19. Adhering to such a regimen will have the greatest impact on their tournament participation in the post-COVID-19 pandemic period.
INTRODUCTION
The COVID-19 pandemic is an unprecedented global crisis in modern times. As we approach the second half of 2021, the SARS-CoV-2 virus had already infected over 21.4 million people worldwide, with more than 4,470,000 deaths [1]. This global crisis has affected every aspect of life, including sports. Historically, major local and international sporting events have been affected, including the Olympic Games in Tokyo, that were postponed until the summer of 2021 [2].
Social distancing measures and suspension of various sports competitions were also implemented in South Korea [3]. In situations wherein it is difficult to ensure adequate training and participation in competitions, players cannot guarantee the maintenance of their performance. It is difficult for college athletes to train on their own and be physically prepared for a collegiate season because many gyms and other training facilities closed owing to regional lockdown regulations. More importantly, being separated from teammates has long-term impacts on team culture and the mental and physical health of athletes [4].
COVID-19 has had a greater impact on weight loss in athletes who lose weight to compete. Athletes from martial arts sports such as wrestling and judo, weightlifting sports such as bodybuilding, and numerous other sports such as gymnastics and track and field, lose weight to improve performance. More than 80% of athletes in weight-related sports practice weight loss [5]. Weight loss requires an increase in activity, a decrease in eating, and facilitation of body fluid loss via sweating; this is achieved by active (exercise-induced) or passive (exposure to hot environments, e.g., sauna) strategies [6].
Most athletes prefer to lose weight for a short period by increasing their physical activity: however, this may be impossible when there are restrictions on physical activity and training facilities are closed. Therefore, it is important to understand how athletes who needed to lose weight during the COVID-19 pandemic lost weight, as losing weight is significant for athletes to improve their performance and competing abilities.
The number of studies on the effects of weight loss in athletes during the COVID-19 pandemic era is insufficient. Most of these studies are based in Western countries [7-10], and research in Asia, including South Korea, is lacking. Specifically, only a few studies have documented the practical information of highly developed elite athletes who conduct daily training. Therefore, this study aimed to examine the physical activity and eating habits of elite athletes pre- and post-COVID-19 outbreak to identify changes in their weight and competing abilities, and to establish a database of this information for the post-COVID-19 pandemic period. Through a comparison with previous studies, this study suggests ways for athletes to make a successful return to tournament participation in the post-COVID-19 period.
METHOD
Participants
This study surveyed adults aged 20 years and older who had been registered as athletes for more than 7 years at the Korean Sport & Olympic Committee. These athletes were divided into a weight loss athletes’ group (WLG) and nonweight loss athletes’ group (NWLG). The classification of weight loss sports was divided into responses to the loss survey and athlete events. A questionnaire was distributed online through the organization secretariat and team coaches of each sport by using a simple random sampling method. A total of 913 responses were employed for data analysis. In total, 383 responses were excluded due to the following reasons: incomplete responses were provided; only the same number was repeated; or, the response was judged to be uncertain based on the judgment of the verification committee. The surveyed athletes were from 22 sports, including individual sports, record sports, ball sports, racket sports, combat sports, and winter sports. Demographic characteristics of the participants are presented in Table 1.
Ethical approval
This study was conducted in accordance with the Declaration of Helsinki guidelines. This study was approved by the Research Ethics Committee of Yongin University (approval no. 2-1040966-AB-N-01-2106-HSR-227-2). Written informed consent was obtained from all the subjects.
Data Privacy and Consent of Participation
We assured the survey participants that all collected data would be used only for research purposes; subsequently, we received the participants’ informed consent. The responses anonymized and their confidentiality was ensured according to Google’s privacy policy (policies.google.com/privacy? hl=en); moreover, the participants were not permitted to provide their names or contact information. Additionally, they were provided the option to withdraw their participation from the study and leave the survey at any stage before submission; if they chose to do so, their responses were not saved. Responses were saved only after a participant clicked the “Submit” button provided in the online form. After completing the survey, all participants were asked to provide their voluntary consent to participate in this study. We requested the participants to answer the survey honestly [11-13].
Survey Questionnaires
The questionnaire used in this study was prepared by modifying and supplementing the questions used in an existing study with respect to the variables used in this study. The questionnaire included items on demographic factors and questions about physical activity, sleep, and eating habits pre- and post-COVID-19 outbreak. A total of 46 subjective questions that required short answers were included in the survey; these are classified as follows: 12 questions on participants’ demographic information; 16 questions on physical activity, sleep, and sitting time; and eight questions on eating habits. Twelve questions on demographic factors [14] were modified and supplemented to suit the subject and context of this study. The 16 questions on physical activity (International Physical Activity Questionnaires-Short Form) and sleep (Pittsburgh Sleep Quality Index) were also modified for this study. The survey questions were based on a short questionnaire on international physical activity and a questionnaire on sleep quality [14-17]. The eight questions on eating behavior [15-18] were modified and supplemented to suit the subject and context of this study. Finally, eight questions on weight change were newly created through feasibility verification by a group of experts, as it was deemed difficult to utilize prior research questions on weight loss.
Validation of feasibility and reliability of survey questionnaires
The validity of the questionnaires used in this study has been demonstrated in earlier studies [9,10]. Therefore, only the content validity verification for translation errors was conducted. Professors and researchers from the fields of exercise physiology, sports nutrition, exercise prescription, and training methodology, and a group of experts composed of coaches and athletes verified the validity. The researchers examined whether the measurement methods and concepts exhibited by the questions were appropriate.
Furthermore, the reliability of the questionnaires was evaluated through a pre-experimental trial conducted by the researchers. The pre-experimental data indicated that the test reliability coefficient of the survey was suitable (r= 0.84 – 0.96).
Statistical analysis
Statistical analyses were conducted by using IBM SPSS (version 25.0, Windows). All data are presented as mean±SD values. Descriptive statistics were used to define the ratio of responses to each question, yielding means and standard deviations for each question. A two-way ANOVA with t-test (post-hoc) was used to identify changes in physical activity, sleep, eating habits, and weight of the athletes pre- and post-COVID-19 pandemic. Statistical significance was set at p<0.05.
RESULTS
Changes in physical activity the post-COVID-19 pandemic period
In the post-COVID-19 pandemic period, the amount of vigorous activity decreased in both WLG and NWLG. Statistical differences were observed in both groups (p<.001). Vigorous activity times also decreased in the post-COVID-19 pandemic period in the WLG (p<.002) and NWLG (p<.037) (Table 2).
The amount of moderate activity also significantly decreased in both groups in the post-COVID pandemic period; in the case of moderate activity time, only the WLG (p< .001) showed statistically significant differences (Table 2).
The amount of light activity decreased in both groups. However, there were no statistically significant differences between the groups in this regard. Light activity time decreased in both groups. Individual sports (p<.001), WLG (p<.001), and NWLG (p<.001) showed statistically significant differences (Table 2).
Changes in lifestyle post-COVID-19 pandemic
The time spent sitting in the post-COVID-19 pandemic period increased in both groups. Additionally, the WLG (p<.001) and NWLG (p<.011) showed statistically significant differences (Table 2). The time spent lying down increased in both groups. Except for the NWLG (p<.011), there were no statistically significant differences (Table 2).
The number of breakfasts consumed was found to have decreased in the WLG in the post-COVID-19 pandemic period. The WLG (p<.001) showed statistically significant differences (Table 2). The number of lunches consumed decreased in the WLG and increased in the NWLG in the post-COVID-19 pandemic period. However, no statistically significant differences were observed between the groups (Table 2). The number of dinners consumed decreased in the WLG and increased in the NWLG in the post-COVID-19 pandemic period; the WLG (p<.001) showed statistically significant differences (Table 2).
Changes in number of competitions participated in in the post-COVID-19 pandemic era
The number of competitions participated in decreased in both groups in the post-COVID-19 pandemic period. The WLG (p<.001) and NWLG (p<.001) showed statistically significant differences (Table 2).
Changes in weight loss and control method in the post-COVID-19 pandemic era
In the post-COVID-19 pandemic period, the WLG and NWLG showed differences in weight changes. In the case of the WLG, the weight loss decreased by 2%—whereas in the NWLG, it tended to increase by 3%. The WLG (p<.001) and NWLG (p<.001) showed statistically significant differences.
The weight loss regimen was investigated only for the WLG. Wearing sweat suits (p<.001), decreased eating (p<.001), vomiting (p<.001), and the use of diuretics (p<.001) all significantly increased in the post-COVID-19 pandemic era, while increased activity (p<.001) and the use of sauna (p<.001) significantly decreased (Figure 1).
DISCUSSION
This study was conducted to establish a current database of elite athletes’ information by identifying their activities, eating habits, and participation in competitions in the preand post-COVID-19 pandemic period and to facilitate the successful return of athletes in the post-COVID-19 pandemic period.
Social distancing guidelines due to the COVID-19 pandemic have had a great influence on the daily lives of the general public and sports activities of athletes [19,20]. These restrictions had diverse effects, one of which was the reduction of physical activity [21], and the destruction of psychological stability [22,23] of athletes. These may manifest as mental illness and post-traumatic disease, inhibiting immune system function [24].
Recent studies have shown a decrease in vigorous and moderate activities since the COVID-19 pandemic. There were significant restrictions on participation in physical activities, including sports, during the pandemic, thereby reducing the number of training days and hours [25,26]. This has resulted in the deterioration of overall athletic activity and physical performance [27].
The mandatory social isolation period, in which an athlete did not have the daily opportunity to receive professional training with a coach or fellow player, was implemented worldwide after the outbreak of COVID-19 [27]. COVID-19 quarantine measures were implemented in sports facilities [28], and social distancing for infection prevention was practiced worldwide, including Korea. The prohibition on the use of training facilities and multi-person gatherings caused a decrease in activity. According to a study by Urbaniski [25], most athletes were unable to train at facilities.
If elite athletes exercise alone, their physical function deteriorates [29]. Therefore, online sports education programs or new communication methods must be developed between coaches and athletes [9] to supervise the level of physical activity in athletes and help them perform personal training [30].
According to one study, the time spent in sedentary positions significantly increased during the pandemic [19]. Similar results were obtained in this study. The sitting time of elite athletes increased by an average of 120 min per week, which may be due to the increased time spent at home due to lockdown restrictions [9]. Online learning in a continuous, non-face-to-face environment also increased the sitting time [25]. The main reason for this is social isolation due to the spread of the COVID-19 virus. The increase in the time spent at home due to quarantine led to a rise in a sedentary lifestyle.
The effect of quarantine on athletes’ mental health was significant. A recent study showed that individuals in social isolation due to COVID-19 suffered from twice as much depression and anxiety as those who were not isolated [31]. Additionally, previous studies have shown that the longer the time spent at home because of COVID-19, the higher was the number and size of meals ingested [32,33]. This can be explained in connection with emotional state; decreased activity and social connection led to increased eating capacity. This study confirmed these results and corroborated that the number of meals consumed increased in the NWLG. In contrast, the WLG showed a decrease in the amount of food consumed. Due to the nature of weight-loss sports, the lack of training may have resulted in a decrease in the amount of food consumed in the WLG.
Therefore, it is necessary to understand the psychological state of athletes and diagnose and manage them accordingly. Moreover, appropriate management by experts, such as psychotherapy or medication, can help mitigate the negative effects of the COVID-19 pandemic on athletes [34].
Various mega-events, including the 2021 Tokyo Olympics, were changed in form as spectators were not allowed. Korea actively responded to quarantine measures, and has been running a professional league since 2020. Professional sports and other elite sports were played according to quarantine regulations; However, the number of games has decreased in the post-COVID-19 pandemic period. This is inevitable in a global pandemic, as the training and medical maintenance of athletes should be prioritized.
In this situation, athletes who require to lose weight to enhance their competing abilities should always manage their weight and prepare in anticipation of competition. In October 2021, the largest event in Korea, known as the 2021 National Sports Festival, was limited because of COVID-19. This decision was tantamount to cancellation because only high school games were played. This was detrimental for athletes who managed their weight during the COVID-19 pandemic. If this situation is repeated, the athletes will weaken physically and mentally. Therefore, it is urgent to educate and prepare countermeasures to maintain the proper weight of athletes and research game management strategies.
Many players showed a change in their weight since the start of the COVID-19 pandemic. Among the athletes who participated in this study, 86.7% had a change in weight; 71.6% of these athletes’ weight increased, and that of 28.4% decreased. Specifically, the number of meals consumed increased in the NWLG. According to a recent study, athletes with a high caloric intake may maintain the same eating program despite exercising less and engaging in comfort eating that occurs due to boredom and stress [7]. In other words, even though athletic activity decreases, they maintain the same eating habits as before, leading to weight gain. This is not only a simple increase in weight. For athletes, weight change plays a highly sensitive role in maintaining athletic function and performance. Additionally, heavyweight athletes are at a higher risk of developing hypertension and maladaptive cardiac remodeling [35,36].
Athletes who have gained weight need management, but those who have lost weight are also the main targets of management. Most athletes who reduce the number of meals consumed lose weight. The weight loss needed to compete entails reducing meals and maintaining a reduced weight, instead of exercising less due to COVID-19 restrictions.
Athletes must obtain both adequate macronutrients (protein, carbohydrates, fats) and micronutrients through a variety of foods [37]. However, continuous eating of small portions can cause nutritional imbalance and abnormalities in physical function. Therefore, nutrition education and guidance are important for athletes who practice weight loss; however, formal clinical training in nutrition is often lacking. Most medical schools in the US (71%) do not provide a minimum of 25 hours of nutrition education, and 36% provide less than half of this required time [38]. Nutrition guidance is difficult in situations where training is restricted because of COVID-19. Therefore, providing appropriate nutrition education for athletes is crucial for the prevention of future diseases.
This study has several limitations. First, the participants were limited to elite Korean athletes. Second, the results were obtained from an online survey that did not require the participants’ personal information. Consequently, there is a possibility of dishonest and duplicate responses. Third, each questionnaire asked about the process of their physical activities only for the past 7 days; physical activity for different periods was not examined, such as 2 weeks or a month. Finally, the physical activities of elite athletes were not classified into daily physical activities and professional physical activities but were based only on intensity. Thus, errors may have occurred regarding “light level activity.”
Athletes must train, nourish, and sleep adequately to maintain their performance. However, routine training was not possible during the extended COVID-19 pandemic. Additionally, weight control and weight loss are factors that need to be controlled in athletes. As weight loss may be considered a professional sporting failure, it is usually one of the most important aspects to manage. However, if athletes harm their health for training and weight loss, it will have a worse impact in the long run. Therefore, athletes must find the best way to maintain physical, physiological, and psychological states close to their original abilities before the pandemic.
However, the COVID-19 pandemic is not yet over. Therefore, to overcome the impact of this pandemic and prevent that of others, it is important to transfer appropriate knowledge to players. Additionally, it is necessary to develop and actively utilize non-face-to-face education methods so that accurate training information can be delivered to athletes to aid them in weight loss and performance improvement.
Acknowledgements
This study received no funding. I would also like to thank Editage (www.editage.co.kr) for the English language editing.