I don't have any idea about how pacemakers actually sense. I mean the mechanics that enable them to assess your required heart rate and proportion it to any increased physical demand. I understand that it sense's through the leads and has an onboard computer but that's about it for now. I must research it a little more as nothing much is explained to you at first about it's potential in terms of adjustments related to lifestyle etc. As a layman l understand that when you exercise you get out of breath and so breath deeper and faster, logically your heart would need to beat faster to get the blood quicker to your organs to oxygenate them more efficiently etc. l don't know what factors the pacemaker can assess other than the hearts electrical activity. For instance, does it have the capability to detect oxygen saturation levels in the blood and make adjustments based on factors like this and are there any algorithms involved? At this stage l simply don't know, but considering that l have only had it a fortnight, it's still early day's for me. In life you obviously work with what you have and l now have something new to consider, and so once l know about it's full potential l intend to make the best possible use of it.