Fatigue countermeasures are strategies used to reduce the effects of fatigue that may already be present. An effective but temporary fatigue countermeasure is physical activity.  This strategy works because it alters our physiology towards the awake state.  Two of the most influential alternations are increases in sympathetic nervous system activation and alertness promoting neurochemicals such as dopamine, norepinephrine, serotonin, histamine and orexin in areas of the brain that control wakefulness.  There may be a dose-response relationship for the effects of physical activity on fatigue, but research has not yet revealed an accurate formula.  There are far too many variables that need to be more fully researched like the severity of fatigue, type and intensity of movement, circadian timing, and individual fitness and health, to quantify the duration of physical activity’s countermeasuring effects.  From my reading of the literature, it is probably safe to assume a generalized ratio of 1 to 2 for moderate physical activity.  A brisk walk, light jog, or calisthenics like jumping jacks for 5 minutes will probably buy you 10 minutes of fatigue countermeasuring effects.

Another generality is that physical activity will keep your workers awake while they are doing it.  In my clinical days, there were many excessively fatigued patients who could fall asleep while moving.  I remember one gentleman clearly.  He was so fatigued that he fell asleep waking into the clinic’s bathroom.  But for most people, physical activity effectively countermeasures fatigue while doing it and for a short time after stopping.

There are two obstacles you may encounter with the physical activity strategy.  The first obstacle is usually suggested by a statement like, “I can’t use this strategy because I can’t just stop what I am doing to exercise”.  I get over this obstacle by pointing out that removing oneself from work to go and exercise would likely require permission from a supervisor or manager.  This would make it an organizational strategy.  When exercise is used as a personal strategy, it is only used during non-work time.  This means, that, if your workers do not have breaks built into their work time, exercise cannot be used as a personal fatigue countermeasure.

The second one is that moderate physical activity can be difficult in small spaces like truck cabs, aircraft cockpits, and equipment crane buckets.  Creativity and the knowledge that even light movements can help countermeasure fatigue can overcome this obstacle.  I usually suggest that when workers are stuck in small space, they think about light movements their bodies would not normally do during sleep and use these to countermeasure fatigue.  Stretching limbs and torsos, arm circles, and clapping hands with extended arms are some of the creative light movements that can be used in small spaces.

One advantage of the physical activity strategy is that it is sometimes easily convertible to an organizational strategy without creating additional non-fatigue related risks.  For example, when work involves long periods of monitoring, very few inputs from the workers and does not require instantaneous responses to urgent situations, organizations can supply equipment that can be used during the monitoring work without increasing other risks.  The supply of equipment makes it an organizational strategy.  My clients have provided their workers with treadmills, free weights, and elastic exercise bands, that have been safely and effectively used after thoughtful risk assessments and establishing agreed upon procedures for safe use.