One of the most important elements affecting performance and recovery in athletes is flight travel for competition.

Both long-distance (Cesarone et al., 2003) and medium-distance flights (Cesarone et al., 2001) have been shown to negatively affects microcirculation as well as circadian rhythms patterns through the disruption of fundamental biological mechanisms like the sleep-wake cycle (Fowler, 2015).

An interesting review by Leatherwood and Dragoo (2013) identified the following mechanisms as negatively affecting performance after airline travel: circadian rhythm disruption, jet lag, sleep deprivation, traveling at altitude and nutritional factors.

Traveling at altitude and muscle stimulation

A long time spent flying at high altitudes can lead to an hypoxic stress to be verified at a cellular level as a consequence of the air cabin pressure environment: hypoxia is defined as a medical condition of the body in which the tissues are deprived of adequate oxygen supply.

The average cabin pressures falls somewhere between 5000-6000 ft, with those values being equivalent to an inspired oxygen pressure (PO2) of 132-127 mm Hg. Oxygen Partial Pressure (PO2) is one of the four main variables describing the oxygen status of arterial human blood, the others being oxygen saturation, hemoglobin content and oxygen content (Zander, 1990).

PO2 is a key factor determining the optimal physiological state of tissue and it results from the balance between oxygen delivery and its consumption (Carreau et al., 2011): the subsequent decline in oxygen saturation levels during long-haul flights has been shown in a prospective study by Geertsema et al. (2008). In this study the level of oxygen saturation in 63 athletes and staff members during a long-haul flight experienced a significant decrease after 3 and 7 hours of flight (see figure 2).

As the time spent on long-haul flights under acute exposure to hypoxia is considered equivalent to time spent at altitude (Geertsema et al., 2008), it is fundamental to adopt intervention strategies in order to avoid the detrimental effects of hypoxia on circulation, peripheral blood flow and performance.

Sometimes athletes arrive at their destination shortly before competitions with not enough time to fully recover. In this case electrical muscle stimulation seems to be actually the best solution for athletes, or anyone, engaging in long-haul flights in economy class: restricted space and limited mobility does not represent an issue as electrodes can be kept in place in advance before departure and then connected to the device during flight.

Using the PainPod in this scenario to maintain optimal blood flow status is extremely simple and it can counteract the detrimental effects of long periods of sitting and hypoxic stress.

I have found the feet and calves stimulation to be the most effective and I normally advise all my athletes to follow this simple protocol during long-haul flights:

• First session of 30 minutes low-intensity stimulation of plantar fascia
• Followed by 30 minutes of calves stimulation after the first 2 hours of flight
• Then 2 hours of rest and
• Restart the cycle.

The multi-factorial aspect of an individual performance and recovery requires coaches to manage every type of stress being imposed on the body and competition travel represents one of the most important stresses imposed on athletes today.

Therefore, the use of PainPod as a means of electrically stimulating muscles is going to provide a great advantage in terms of recovery time and physiological health status.

Moreover, using PainPod during flights is extremely useful for general the population as well (i.e. frequent flyers, air travellers) in order to avoid the undesirable effects of microcirculatory alterations associated with edema (Cesarone et al., 2001): some of the effects associated with medium-to-long distance flights include stasis, thrombosis, edema and microcirculatory disturbances (Belcaro et al., 2001).

As passengers experience edema mostly with ankle and foot swelling, using muscle stimulation with the PainPod by placing pads over the plantar fascia, it can be very effective in counteracting disturbances created by microcirculatory alterations during long-haul flights.