Multiple sclerosis (MS) is defined as a demyelinating, progressive and neurodegenerative disease. Cognitive impairment has been recognized as a common clinical feature of MS. It is present in 65% of patients and on the other hand, about 52%–97% of MS patients show symptoms of bowel/ bladder deficits, such as retention or incontinence and the most common urinary disorder present in MS patients is urinary incontinence which is related to fatigue and uncoordinated muscle recruitment. Lower urinary tract symptoms (LUTS) including frequent urination, nocturia and urge urinary incontinence negatively impact quality of life. To explore the effects of a six weeks moderate-intensity aerobic exercise intervention on Urinary incontinence related biomarkers specifically cortisol using a pilot randomized controlled trial

Participants were randomly allocated to either a moderate-intensity aerobic exercise program (MAE, n = 20) or a home exercise program (HEP, n = 20). Participants were assessed at baseline and follow-up. Urinary incontinence was assessed using the International Consultation on Incontinence Questionnaire (ICIQ). Blood samples were collected for measurement of cortisol from MS participants in both groups at 8:00 am±1 hour.

Seventeen participants in the MAE and 13 in the HEP group completed the study. Compared to the HEP group people with MS who participated in a moderate-intensity aerobic exercise experienced significant improvements (P < 0.05) on the ICIQ.

Furthermore, the cortisol level increased significantly over the six-week period in the MAE group compared to the HEP group. The change score in the cortisol level (from baseline to follow up assessment) was significantly correlated with the change score in ICIQ (r = –0. 56, p = 003) only in the MAE group but not the HEP group.

Many studies were done to assess the effect of aerobic training and home exercise program on patients with MS. Although no study correlates the effect of either directly on UI, it can be stated that certain aerobic training increase overall physical activity and cardiovascular effort, prevent general muscular weakness and reduce health risks due to deconditioning and disuse. Furthermore, a supervised and individualized exercise program can reduce fatigue and increase quality of life. Since aerobic training helps in the previously mentioned aspects, it can be concluded that AT will allow patients with MS to be more independent and have the energy to go to the bathroom, possibly reducing the effect of functional incontinence. Exercise may be a non-pharmacological, inexpensive, safe method to improve UI  in people with MS. The improvement in the cortisol level due to aerobic exercise might explain one of the physiologic mechanisms driving these improvements.