| Grade | Degree | Characteristics |
|---|---|---|
| 0 | None | Only with strenuous activity |
| 1 | Slight | When hurrying on level ground or climbing a slight incline |
| 2 | Moderate | Needs to walk more slowly than others of the same age or has to stop for breath when walking at own pace on level ground |
| 3 | Severe | Stops for breath after 100 yards or after a few minutes |
| 4 | Very severe | Housebound or dyspnea when dressing or undressing |