# Practical Approach to Designing and Implementing a Recommendation System for Healthy Challenges
###### Abstract
In the current literature, various proposals can be found aimed at promoting these mentioned healthy habits. Examples of such initiatives include Public GYM [26], PRECIOUS (PREentive Care Infrastructure Based On Ubiquitous Sensing) [27], Fit brains trainer [28], Sworkit Lite [29], SAFER (Smart Assistance Platform for EldeRly Care) [30], HyperRecSysPA (PA Recommender System for Patients With Arterial Hypertension) [31], Mind Match [32], and Mindcraft [33]. These proposals can be classified into three groups according to the domain of human health they affect, pertaining to PA, mental health and nutrition. In the first group, among the proposals related to the practice of PA, we have Public GYM [26], which is a mobile recommender system (hereafter RS) that employs artificial intelligence techniques to offer personalized exercise routines to users, specifically targeting PA in public outdoor gyms. The system takes into consideration the user's anthropometric characteristics and specific medical conditions. For example, a diabetic user would receive customized strengthening exercises that avoid targeting areas where insulin is typically administered. Another proposal is PRECIOUS [27], an Android application developed to promote a healthier lifestyle. This application analyzes various factors such as diet, PA, stress levels, sleep patterns, and environmental conditions to evaluate the user's current health status. Based on this analysis, the application suggests activities that can contribute to enhancing overall well-being. The recommended activities are tailored to combat type 2 diabetes and cardiovascular diseases. Sworkit Lite [29] is a fitness application focused on physical strengthening. It offers a range of routines including strength exercises, cardio workouts, stretching, and yoga. Users can select the specific body area they wish to exercise, and the system provides a set of routines along with recommended durations for optimal results. Lastly, HyperRecSysPA [31] is a PA RS specifically designed for hypertensive patients. The system collects relevant information from hypertensive individuals to provide personalized recommendations for PA based on their specific needs and conditions. In the second group, regarding mental health, we encounter Fit brains trainer [28], which is an application designed to enhance the cognitive capacity of older adults. The application presents users with memory-testing games that progressively increase in difficulty as they successfully complete each level. The system continuously monitors and analyzes the user's progress, and based on their performance, suggests new games that align with their capabilities. SAFER [30] is an RS that focuses on recommending recreational and cultural events for seniors. Its objective is to suggest cultural activities based on the user's preferences and the availability of events in the city. Mind Match [32] aims to promote mental health among adolescents to help them develop healthy habits and coping mechanisms for the future. Mind Match incorporates mental health education into the high school curriculum to ensure every student accesses the resources needed to understand their mental health. And finally, Mindcraft [33], is a mobile mental health platform for children and young people, which integrates passive sensor data monitoring with active self-reported updates through an engaging user interface to monitor users' well-being. In the third group, regarding healthy eating, we came across the research conducted by [PERSON] et al. [34], in which they developed a food recommendation system tailored for the elderly population. Drawing upon behavioral characteristic data, the system generates various clusters to provide dietary recommendations to each of them. Another study focused on healthy nutrition is that of [PERSON] et al. [35], in which they employed smart plates to assess the eating habits of young children. They weighed the plate before and after each meal to calculate the amount of food consumed by the child.