Abstract: During the COVID-19 pandemic, there has been a notable rise in health risk behaviors among children and adolescents, and despite the gradual resumption of regular life, their impacts still endure. It is valuable to investigate and scrutinize a range of inquiries concerning the shifts in health risk behaviors among young individuals under the context of the COVID-19 pandemic, the reasons behind the emergence of these behaviors, and their continuity. This article initially outlines in a systematic manner the features of different prominent health risk behaviors among children and adolescents during the COVID-19.
In relation to screen time, there was a notable rise in total screen time among children and adolescents, particularly impacting primary school children during the COVID-19 pandemic. Concerning physical activity, there was insufficient engagement in physical activities among children and adolescents, accompanied by a rise in sedentary behaviors. The decline in moderate to vigorous physical activity was most evident, and with increasing age, children participated less in physical activities. Regarding dietary habits, there was a decrease in the consumption frequency of fresh vegetables, fruits, legumes, and dairy products among children and adolescents during the pandemic. They were consuming more snacks, and the COVID-19 pandemic influenced their eating patterns, resulting in changes in appetite, irregular eating routines, heightened emotional eating, and a propensity towards deteriorating dietary habits as age grow older. In terms of sleep, the COVID-19 pandemic significantly altered the sleep patterns of children and adolescents. These alterations include later bedtimes, waking up later, longer sleep durations, reduced sleep quality, and a notable increase in the prevalence of sleep issues.
Next, based on analyzing existing research, the article further extends the conceptual framework of family risk and resilience during the COVID-19 pandemic, and then proposes a family risk framework for children and adolescents' health risk behaviors in the context of the COVID-19, which analyzes the causes of children and adolescents' health risk behaviors from a family risk perspective under the epidemic background. This framework posits that such health risk behaviors during the COVID-19 were inseparable from the infiltration of risks in the proximal caregiving environment. Within the caregiving environment, parental behaviors marked by "lenient rules" and "harsh punishment," poor parent-child communication, and heightened parent-child conflicts played pivotal roles in influencing changes in health risk behaviors among children and adolescents. Factors such as increased caregiver stress, declining emotional well-being, were key. Deteriorating economic circumstances, food insecurity, and modifications in work and education all contributed to facets of this process. Beyond scrutinizing the unique alterations in the caregiving environment during the pandemic, it is crucial to acknowledge that existing family vulnerabilities can worsen the impact of changes in family risks on children and adolescents' health risk behaviors during the epidemic.
Finally, we try to combine the proposed framework with life history theory to explain the sustained effects of health risk behaviors of children and adolescents in the post-epidemic era from the perspective of dynamic development. For children and adolescents, the COVID-19 epidemic occured in the early stages of their growth, and the COVID-19 epidemic has a profound impact on families. The problems caused by living conditions reflected the harshness of the development environment of children and adolescents during the COVID-19 epidemic. The deteriorating mental state of caregivers and the negative parental behaviors reflect the unpredictability of the environment, Promoting children and adolescents to be more inclined to adopt fast life history strategies in their subsequent lives, which may be the key to the persistence of health risk behaviors in children and adolescents after the COVID-19 epidemic.
Future research should conduct comprehensive exploration of health-related behaviors pre and post the COVID-19 pandemic, enhance in-depth research on the family risk framework of children and adolescents' health risk behaviors under the background of the COVID-19, and provide multi-faceted support for the healthy development of children and adolescents at the practical level. This article provides a systematic observation and theoretical perspective on the development of healthy behaviors in children and adolescents, helping to understand the reason of changes in health risk behaviors during special periods. It provides a scientific basis for targeted family interventions and offers general solutions for handling children and adolescents' health issues during future similar emergencies.

Key words: COVID-19, health risk behaviors, children and adolescents, family risk, life history theory