Since the 1990s the U.S. military has been developing equipment to monitor the physical condition of troops in stressful situations. This is not easy, because “stressful” usually means combat. There has been a lot of progress since 2001 and the goal of such PSMs (Physiological Status Monitors) is to make them useful (provide needed data), reliable, wearable in combat, unobtrusive (does not interfere with combat activities), sustainable (battery power) and affordable. Getting this kind of technology to the point where troops, especially infantry in combat, can use it regularly often takes a decade or more from the first version capable of being actually carried or worn by troops, to one that becomes a regular part of their combat gear. PSMs aren’t there yet, but they are getting close.
With equipment like PSM progress comes in stages, often with help from similar technology that is useful in training or becomes standard gear for some civilian occupations. For example PSMs that measure a lot of the stresses combat pilots experience, including respiration, air supply and quality, G (gravity) forces and various factors contributing to stress or disorientation, are becoming practical. Not so much for every pilots on every flight but for test pilots or for situations where some kind of problem is suspected but the nature and source is vague. Such PSMs were useful in finding out what was causing pilot air supply problems on certain types jet fighters over the last few years. PSMs were also a practical tool for use in exploring better solutions to handling high-heat situations and the dehydration, disorientation and disabling (and sometimes fatal) effects. PSMs have been used to test new recruits undergoing basic and advanced combat training to see if they are physically able to handle high heat conditions.
PSMs have proven that, like so many other capabilities, some people are better able to cope with heat problems, even if some require additional training and conditioning to do so. Some troops just don’t have the capability. PSMs make it possible to get a better idea of what the limits are and who has them to what degree. Such lack of innate physical capabilities has always been an issue in sports, many civilian occupations and the military. For centuries there were tests that became more and more effective at determining who could handle what. Thus the most difficult military jobs (fighter pilot, special operations troops) have a lot of aspirants who never make it through all the training.
Some of the latest PSMs have been easier to wear and durable but they are still expensive and some don’t last long in combat. For example a pill containing a number of sensors, which you swallow and measure internal conditions as the pill passes through the digestive system would be difficult to reuse in combat, especially since these pass through the digestive system within 48 hour. Another PSM that collects numerous bits of data is similar to the chest strap type heart rate monitors that athletes (amateur and pro) have been using for over decade. These capabilities are not built into some watches (FitBit) and items like this have evolved to measure all sorts of stuff. Again, they are OK for many civilian and military uses, but not quite ready for the rigors of sustained ground combat.
Even with the growing number of developing, or very specialized PSMs these devices have been having growing impact on obtaining practical data that saves lives. In 2008, for example, 1,145 American paratroopers had a 17 g (6 ounce) PSM added to the back of their helmets. They wore the device for over a year (their entire tour of duty in Afghanistan). The tiny sensor package could record 527 different types of movement. In particular, U.S. Army medical researchers were interested in what happens when troops are hit by the blast of an explosion. There had been a lot of that since 2003 because of the wide use of roadside bombs by terrorists. The troops had to download data from the device once a month while the battery lasted six months. This PSM device was the first test of a long planned effort to equip troops with medical sensors, in order to assist in treatment for battlefield wounds. Sort of like a "black box" for those on the battlefield. These devices will ultimately hook into the battlefield Internet, and alert medics, and medical personnel in general, that someone is hurt, to what extent and where they are. These devices, as the current use shows, are also able to collect precise injury data for research on trends, and the details of the injury process. This makes it possible to build better protective devices (helmets and body armor) and develop more effective treatments.
The goal of a system that would constantly monitor soldier health and make that data available to commanders and medics in real time is still somewhere in the future, as the goal of electronic military health records that be updated automatically and accurately during medical treatment.