Effects of Aging on Pain Tolerance: A Comparative Study of Heat Pain Thresholds and Tonic Heat and Cold Stimuli.

INTRODUCTION: Aging is known to impact both pain perception and modulation. While sensory thresholds have been extensively studied, age-related changes in pain tolerance remain less conclusive. Additionally, limited research has explored whether thermal modality differentially affects pain tolerance in older adults. This study aimed to examine modality-specific effects of aging on pain tolerance using three experimental paradigms: thermal pain tolerance thresholds, and tolerance to tonic heat and cold stimulation. METHODS: Forty-two healthy participants were recruited. Heat pain tolerance thresholds were assessed using a contact thermode. Tonic pain tolerance was measured by exposing the hand to heat or cold air for up to 10 min in a hermetically sealed box. Outcome measures included tolerance duration, pain onset latency, and subjective pain ratings. RESULTS: No significant age-related differences were observed in heat pain tolerance thresholds. However, older adults exhibited significantly reduced tolerance to prolonged heat stimulation, with shorter tolerance durations and higher pain ratings. In contrast, pain responses in the cold condition did not differ between age groups. CONCLUSION: Aging appears to selectively reduce tolerance to sustained heat stimulation, whereas tolerance to cold and brief stimuli is relatively preserved. This supports the existence of modality-specific changes in pain processing across the lifespan. SIGNIFICANCE: These results underscore the importance of stimulation characteristics in evaluating pain tolerance across the lifespan. The study highlights an underexplored heat-specific vulnerability in older adults, offering insights for refining experimental pain models, improving age-sensitive assessments, and encouraging further research into physiological mechanisms underlying altered pain processing in aging.