Use a lower frequency stimulation (2-5Hz) with wider (longer) pulses (200-250ms). The intensity employed will usually need to be greater than with the traditional TENS - still not at the patients threshold, but quite a definite, strong sensation. As previously, something like 30 minutes will need to be delivered as a minimally effective dose. It takes some time for the opioid levels to build up with this type of TENS and hence the onset of pain relief may be slower than with the traditional mode. Once sufficient opioid has been released however, it will keep on working after cessation of the stimulation. Many patients find that stimulation at this low frequency at intervals throughout the day is an effective strategy. The ‘carry over’ effect may last for several hours, though the duration of this carry over will vary between patients.