Which disease characteristically shows an early RPE of 6-8/10 and 60-80% HRmax?

• A. PD
• B. MS
• C. ALS
• D. Post Polio

Answer: (B)

In multiple sclerosis, fatigue and reduced endurance are common, and the way the body uses energy during activity is altered by demyelination and central fatigue. Because nerve conduction is slower and more energy is required for movement, a person with MS often feels a relatively high effort at lower workloads. That means they can reach a moderate exercise intensity (about 60–80% of their max heart rate) while still reporting a fairly noticeable effort, around 6–8 on a 10-point RPE scale. This combination—moderate heart-rate intensity paired with a fairly high perceived exertion early in an activity—reflects the characteristic fatigability and impaired efficiency seen in MS.

Other conditions may involve exercise tolerance changes, but the pattern described is most typical of MS. For example, in Parkinson’s disease autonomic changes can occur, but the hallmark fatigue- and endurance-related pattern with early high RPE at submaximal HR is more characteristic of MS. ALS involves progressive, rapid weakness with decreasing muscle function rather than a distinct early fatigue pattern tied to submaximal heart rate, and post-polio fatigue tends to be a later development after baseline recovery rather than an inherent, early fatigability pattern tied to submaximal exertion.