Aggressive technology and supply voltage scaling has led to increasing concern for reliability. Optimizing power and energy with sub-threshold (sub-VT) operation exponentially increases the occurrences of both static and dynamic failures. With smaller node capacitances with each technology and supply scaling node, radiation-induced Single Event Upset (SEU) has become a critical design metric for Ultra-Low-Power (ULP) applications. In this paper, we explore the impact of radiation-induced soft errors on sub-threshold SRAM implemented in a Body Sensory Node (BSN) as an ULP application. We also demonstrate an exponential reduction in the critical charge (Qcrit) of a storage node with supply in near- and sub-VT design, resulting in a significant design consideration for the low-power applications. The huge process variation in sub-VT results in 3X Qcrit variation. Finally, we compare the trend of technology scaling and supply voltage scaling on Qcrit.