The introduction of wearables in the consumer market has led to an exponential proliferation of connected healthcare devices. They can monitor the status of health ubiquitously and provide insights about long-term and short-term health issues. The time-critical nature of such a system can save lives by generating timely alerts in case of health anomalies. To achieve this objective, in this paper, we specify quality of service (QoS) requirements and present a three-layer design framework of Healthcare Internet of Things (H-IoT) networks. Furthermore, we identify the key enabling technologies to support real-time communication in IEEE 802.11 wireless local area networks (WLANs) such as multi-link operation (MLO), orthogonal frequency division multiple access, spectrum expansion, and enhancing channel utilization over Wi-Fi networks. Moreover, we present a representative case study on the ambient assisted living (AAL) scenario, where the efficacy of MLO is considered to achieve ultra-low latency in a Wi-Fi-based H-IoT network. This study provides a template for other health-related applications that are strictly latency-bound, such as remote surgeries, e-consultations, and countering pandemics.