Improving Personalised Physical Activity Recommendation on the mHealth Information Service Using Deep Reinforcement Learning

Recently has seen the growth in the use of mobile health (mHealth) information services, which have rich guides on improving physical activity. These rich guides evolved from the consideration of various personal behavioural factors, which often deviate from the user's health conditions. The behavioural factors include changing fitness preferences, adherence issues, and uncertainty about future fitness outcomes, which may all lead to a decline in the quality of the mHealth information services. Many of these mHealth information services provide limited fitness guidance owing to the dynamics of the user's health conditions. This paper seeks an adaptive method using deep reinforcement learning to make personalised physical activity recommendations, which is learnt from retrospective physical activity data and can simulate realistic behaviour trajectories. We construct a real-time interaction model for the mHealth information service system based on scientific knowledge about physical activity to evaluate its exercise performance. The physical activity performance evaluation model is used to find the optimal exercise intensity considering the fitness and fatigue effects to avoid the lack of exercise or overload. The short-term activity plans are made using deep reinforcement learning and personal health conditions that change over time. Using this method, we can dynamically update the physical activity recommendation policy in accordance with the real implementation behaviour. Our DRL-based recommender policy was validated by comparison to other benchmark policies. Experimental results show that this adaptive learning algorithm can improve recommendation performance over 4.13 percent.