LifeAgentBench: A Multi-dimensional Benchmark and Agent for Personal Health Assistants in Digital Health
Ye Tian, Zihao Wang, Onat Gungor, Xiaoran Fan, Tajana Rosing
TL;DR
LifeAgentBench introduces a large-scale, cross-domain, long-horizon health reasoning QA benchmark built on lifelog data, enabling systematic evaluation of LLM-based health assistants. It reveals that current LLMs struggle with multi-domain aggregation and long-horizon reasoning, even with tool-augmented prompting. To address this, the authors propose LifeAgent, a training-free agent that decomposes complex queries into multi-step, evidence-grounded retrieval with deterministic aggregation, achieving substantial improvements over standard baselines. The work demonstrates practical potential for digital health assistants and provides a reproducible benchmark and agent framework to drive future research.
Abstract
Personalized digital health support requires long-horizon, cross-dimensional reasoning over heterogeneous lifestyle signals, and recent advances in mobile sensing and large language models (LLMs) make such support increasingly feasible. However, the capabilities of current LLMs in this setting remain unclear due to the lack of systematic benchmarks. In this paper, we introduce LifeAgentBench, a large-scale QA benchmark for long-horizon, cross-dimensional, and multi-user lifestyle health reasoning, containing 22,573 questions spanning from basic retrieval to complex reasoning. We release an extensible benchmark construction pipeline and a standardized evaluation protocol to enable reliable and scalable assessment of LLM-based health assistants. We then systematically evaluate 11 leading LLMs on LifeAgentBench and identify key bottlenecks in long-horizon aggregation and cross-dimensional reasoning. Motivated by these findings, we propose LifeAgent as a strong baseline agent for health assistant that integrates multi-step evidence retrieval with deterministic aggregation, achieving significant improvements compared with two widely used baselines. Case studies further demonstrate its potential in realistic daily-life scenarios. The benchmark is publicly available at https://anonymous.4open.science/r/LifeAgentBench-CE7B.
