Effect of the COVID-19 pandemic on weight loss of Korean athletes: changes in athletes’ physical activity and eating behavior

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Abstract

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.

Table 1.

The demographic characteristics of the participants.

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).

Table 2.

Changes in physical activity and lifestyle post-COVID-19.

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 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).

Figure 1.

Changes in weight lose methods post-COVID-19.

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.

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