Since oxidative stress worsens ALS progression, researchers have suggested that intense physical activity may exacerbate oxidative damage. Though, continuing evidence in recent years has suggested that moderate physical activity is beneficial for this population (de Almeida et al., 2012). Flexibility exercise can improve range of motion and reduce muscle tightness, and should be prescribed to all persons with ALS (de Carvalho et al., 1999). Cardiovascular exercise (moderate intensity) for people with ALS has been suggested to delay the progression of respiratory failure (Pinto et al., 1999). Sparse literature has also found minor gains in respiratory impairment (Cheah et al., 2009). When comparing a running and swimming program in mice with ALS, Deforges and colleagues (2009) found that swimming training had benefits associated with disease progression, weight control, motor function, and was able to increase the lifespans of the mice by 20%. Another study by (Drory et al., 2001) and colleagues demonstrated that a regular home based exercise program of moderate intensity, slowed the deterioration on the ALS functional rating scale, which is similar to results found from moderate-intensity resistance exercise alone (Aitkens et al., 1993). Exercise may delay disease progression, promote weight control, preserve motor function, and improve the quality of life in persons with ALS. Clinical interventions are needed to examine the effects of exercise on physiological outcomes and quality of life in persons with ALS, to develop suitable exercise guidelines.

It is important to note that, physical activity involves motor neuron activation, which invokes oxidative stress. This, increase in free radical production and glutamate is usually regulated by homeostasis of the body, but does not occur in persons with ALS with a high risk of developing neurotoxicity (Chen et al., 2008; Dalbello et al., 2008). More research is needed to determine which exercises are beneficial or harmful to persons with ALS. With the current knowledge at hand, it may be best to prescribe no higher than moderate-intensity exercise to persons with ALS. There are currently trials underway, such as the FACTS-2-ALS trial, which may change our understanding of exercise and ALS in the near future.