OBJECTIVES: This study investigated subjective and physiologic responses of lying on a bed of nails (BN) called the Shakti-mat and of listening to relaxing instructions and music. The BN has 6210 sharp-edge 5-mm plastic nails about 5 mm apart. DESIGN: Thirty-two (32) healthy participants went through four conditions in randomized orders combining BN and relaxing instructions. RESULTS: The subjective pain ratings on the BN increased immediately and reached a peak within 30 seconds. The pain then subsided gradually, indicating a habituation effect. Self-rated relaxation increased over time in all conditions. Systolic and diastolic blood pressures were higher, heart rate was slower, and there was more high-frequency power heart rate variability (HRV), and signs of increasing circulation in the back on the BN. The relaxation instruction especially affected breathing and the HRV-indices standard deviations of normal interbeat intervals and low-frequency power, both known to be responsive to slow breathing. There were no differences in saliva cortisol. CONCLUSIONS: Healthy participants habituated to the induced pain on the BN and were able to subjectively relax. When on a BN, signs of both sympathetic and parasympathetic nervous system activity were observed. The pain may hypothetically have triggered a parasympathetic response.