Exercising the MIM (PSSM2) Horse

There has not been much research done into the effects of exercise on horses with PSSM2/MIM. Considering the underlying issue of muscle breakdown, it seems counterproductive to exercise these horses when they appear stiff. Where a horse with PSSM type 1 can benefit from additional exercise to free up glycogen from its muscles, causing it to feel better,  it seems logical that adding exercise to a horse with PSSM2/MIM will only lead to more muscle damage.

Note: during an acute episode of tying up it does not matter what muscle issue is involved: the horse has to stop moving in order to prevent further damage.

Based on owner experiences, a good rule of thumb for horses with PSSM2/MIM seems to be: regular exercise with enough recovery time between strenuous activities. Muscle conditioning is based on generating a light degree of muscle damage, which allows the body to rebuild muscle tissue stronger. Due to the nature of the underlying disease , the rebuilding phase can take longer in horses with PSSM2/MIM.