Tingling feet when in the prone position?

A lot of factors can cause foot tingling. The causes vary from simplest to most serious health complications that may be debilitating or health damaging.Your client should seek a professional medical advice of a licensed doctor to ensure that her foot tingling is not due to a serious medical condition

First, for the sake of understanding, let's specify that PAD means peripheral arterial disease. As to PVT, it can mean pressure-volume-temperature, whereby temperature rises with exercise (Boyles law: pressure of gas is inversely proportional to its volume). Otherwise, PVT can also mean paroxysmal ventricular tachycardia (or PSVT: paroxysmal supraventricular tachycardia).
In case of Boyles law, as one increases exercise intensity, gas pressure increases in the lungs, which increases gas volume. This phenomenon happens, for instance, when a diver rises to the surface of the water and the gas volume expands in the lungs (similar in sudden changes of altitude). Furthermore, as per the oxyhemoglogin curve, an increase in body temperature results in a decrease in the ability of hemoglobin to hold oxygen in tissues. In the case of PAD and increased exercise intensity, body temperature increases and oxygen availability decreases in an environment where blood needs to travel through narrower and stiffer vessels. All together, this means increased risk of cramps, especially in legs, and other complications.
In case of Paroxysmal Ventricular Tachycardia, which is a type of rapid heart rate, this may indicate a problem with blood flow and heart condition.
Indeed, in PAD and both cases of PVT, there is no obvious explanation for tingling in the feet in a prone position. Tingling in the feet may be a problem with pinched spinal nerves, on the other hand. If the individual is prone with legs extended, this may cause the lower back to arch, which may further pinch some nerves. In any case, I would recommend a medical consultation.