SUPPRESSION OF SHIVERING BY BREATH-HOLDING, RELAXATION, MENTAL ARITHMETIC, AND WARM WATER INGESTION

Four methods of suppressing cold-induced shivering were evaluated in 2 6 young male volunteers exposed to 0.0 +/- 1.0 degrees C air for 135 m in. Voluntary relaxation of musculature (R), breath holding (BH), warm (50 degrees C) water ingestion (W), and performance of a mental arith metic task (MA) were applied in ct counterbalanced order following 2 h of cold exposure. Surface electromyograms of seven muscles were recor ded and converted to root mean square voltage (RMS) as a measure of sh ivering intensity. Mean skin and rectal temperatures decreased signifi cantly, 4.9 degrees C and 0.3 degrees C, respectively (p less than or equal to 0.01). Mean reduction of EMG activity wets 35% during R, 24% during BH, 18% during MA, and 5% during W. R was significantly more ef fective than BH, MA, and W, and BH and MA were significantly more effe ctive than W in reducing shivering. These results indicate that, at sm all decreases in rectal temperature, shivering can be voluntarily supp ressed to some extent during relaxation, breath holding, and mental ar ithmetic,