diff --git a/src/browser/Viewport.ts b/src/browser/Viewport.ts
index bea5d99d..063fbc66 100644
--- a/src/browser/Viewport.ts
+++ b/src/browser/Viewport.ts
@@ -232,7 +232,7 @@ export class Viewport extends Disposable implements IViewport {
     if ((modifier === 'alt' && ev.altKey) ||
         (modifier === 'ctrl' && ev.ctrlKey) ||
         (modifier === 'shift' && ev.shiftKey)) {
-      return amount * this._optionsService.options.fastScrollSensitivity;
+      return amount * Math.max(1, this._optionsService.options.fastScrollSensitivity);
     }
     return amount;
   }