温度对心率和心率变异的影响

心率变异（heart rate variability,HRV）是判断自主神经活动最好的定量指标,有时域、频域和非线性等研究方法.频域方法适用于短时程记录,而时域法对分析长时程记录较为理想.HRV的发生基础是自主神经对心率的调节作用,反映了神经体液因素与窦房结相互作用的平衡关系.心率变异受诸多外周和中枢因素的影响,体温及环境温度的变化影响着心血管活动的调节,是HRV的重要起因.极低频（very low frequencies,VLF）功率受温度刺激（如低体温和体温调节活动）的调制,皮肤降温不会特异的影响此频带,表明功率谱中特别频带的改变依赖于体温调节激发模式,而不是体温调节本身.中枢神经系统的损伤可引起心脏自主神经的异常活动并降低HRV,低体温处理可以使HRV的降低更显著.因此研究体温及环境温度与HRV的关系具有非常重要的实用价值.

The Effect of Temperature on Heart Rate and Heart Rate Variability

Heart rate variability(HRV) is the best quantitative index for estimating the activity of the autonomic nervous system,with time domain method(more desirable for long-term recordings),frequency domain method(suitable for short-time recording),nonlinear method for the study of HRV.The physiological foundation of HRV is the regulation of autonomic nervous sytem to the heart rate,which reflects the balance of the interaction between the neurohumor and the sinus node.HRV is affected by many peripheral and central factors.The changes of the body and ambient temperature affect the regulation of cardiovascular activity,which is the important origin of HRV.Very low frequencies(VLF) is modulated by thermal stimuli which result in core hypothermia and thermoregulatory activity,while skin-surface cooling does not selectively modulate this frequency band.The change in particular frequency bands of the power spectra depends upon the mode of thermoregulatory challenge,and not thermoregulation per se.Injury of central nervous system can induce abnormal function of automatic nerve of heart and reduction of HRV,and hypothermia therapy can reduce HRV more greatly.