diff --git a/backend/routers/activity.py b/backend/routers/activity.py
index c3b57a0..b2e2009 100644
--- a/backend/routers/activity.py
+++ b/backend/routers/activity.py
@@ -9,7 +9,7 @@ import uuid
 import logging
 from typing import Optional
 
-from fastapi import APIRouter, HTTPException, UploadFile, File, Header, Depends
+from fastapi import APIRouter, HTTPException, UploadFile, File, Header, Depends, Query
 
 from db import get_db, get_cursor, r2d
 from auth import require_auth, check_feature_access, increment_feature_usage
@@ -32,24 +32,45 @@ logger = logging.getLogger(__name__)
 
 
 @router.get("")
-def list_activity(limit: int=200, x_profile_id: Optional[str]=Header(default=None), session: dict=Depends(require_auth)):
-    """Get activity entries for current profile."""
+def list_activity(
+    limit: int = Query(200, ge=1, le=50_000),
+    days: Optional[int] = Query(None, ge=1, le=4000, description="Nur Einträge mit date >= HEUTE − days (Kalendertage)"),
+    x_profile_id: Optional[str] = Header(default=None),
+    session: dict = Depends(require_auth),
+):
+    """Get activity entries for current profile. Optional *days* filter by calendar window (not the same as *limit*)."""
     pid = get_pid(x_profile_id)
     with get_db() as conn:
         cur = get_cursor(conn)
 
-        # Issue #31: Apply global quality filter
+        # Issue #31: Apply global quality filter (profile from DB = saved level)
         cur.execute("SELECT * FROM profiles WHERE id=%s", (pid,))
         profile = r2d(cur.fetchone())
         quality_filter = get_quality_filter_sql(profile)
 
-        cur.execute(f"""
-            SELECT * FROM activity_log
-            WHERE profile_id=%s
-              {quality_filter}
-            ORDER BY date DESC, start_time DESC
-            LIMIT %s
-        """, (pid, limit))
+        if days is not None:
+            cur.execute(
+                f"""
+                SELECT * FROM activity_log
+                WHERE profile_id=%s
+                  {quality_filter}
+                  AND date >= (CURRENT_DATE - %s::integer)
+                ORDER BY date DESC, start_time DESC
+                LIMIT %s
+                """,
+                (pid, days, limit),
+            )
+        else:
+            cur.execute(
+                f"""
+                SELECT * FROM activity_log
+                WHERE profile_id=%s
+                  {quality_filter}
+                ORDER BY date DESC, start_time DESC
+                LIMIT %s
+                """,
+                (pid, limit),
+            )
         return [r2d(r) for r in cur.fetchall()]
 
 
diff --git a/backend/version.py b/backend/version.py
index 5f465cd..b9fc054 100644
--- a/backend/version.py
+++ b/backend/version.py
@@ -19,7 +19,7 @@ MODULE_VERSIONS = {
     "weight": "1.0.3",
     "circumference": "1.0.1",
     "caliper": "1.0.1",
-    "activity": "1.1.0",
+    "activity": "1.2.0",  # GET /activity: optional days= window + limit
     "nutrition": "1.0.2",
     "photos": "1.0.0",
     "insights": "1.3.0",
diff --git a/frontend/src/components/TrainingTypeDistribution.jsx b/frontend/src/components/TrainingTypeDistribution.jsx
index 0c07780..271c3fc 100644
--- a/frontend/src/components/TrainingTypeDistribution.jsx
+++ b/frontend/src/components/TrainingTypeDistribution.jsx
@@ -15,8 +15,10 @@ export default function TrainingTypeDistribution({ days = 28 }) {
   const [loading, setLoading] = useState(true)
 
   useEffect(() => {
+    const safeDays = Math.max(1, Math.min(4000, Number(days) || 28))
+    const limit = Math.min(50_000, Math.max(250, safeDays * 25))
     Promise.all([
-      api.listActivity(days),
+      api.listActivity(limit, safeDays),
       api.getTrainingCategories()
     ]).then(([activities, cats]) => {
       setCategories(cats)
@@ -43,7 +45,7 @@ export default function TrainingTypeDistribution({ days = 28 }) {
       console.error('Failed to load training type distribution:', err)
       setLoading(false)
     })
-  }, [days, activeProfile?.quality_filter_level])  // Issue #31: Reload when quality filter changes
+  }, [days, activeProfile?.quality_filter_level, activeProfile?.id])
 
   if (loading) {
     return (
diff --git a/frontend/src/components/pilot/PilotActivitySection.jsx b/frontend/src/components/pilot/PilotActivitySection.jsx
index f934d05..f4e23a6 100644
--- a/frontend/src/components/pilot/PilotActivitySection.jsx
+++ b/frontend/src/components/pilot/PilotActivitySection.jsx
@@ -21,8 +21,8 @@ export default function PilotActivitySection({ refreshTick = 0, chartDays = BODY
     let cancelled = false
     ;(async () => {
       try {
-        const fetchDays = Math.max(120, periodDays + 60)
-        const a = await api.listActivity(fetchDays)
+        const limit = Math.min(50_000, Math.max(200, periodDays * 25))
+        const a = await api.listActivity(limit, periodDays)
         if (!cancelled) setActivities(Array.isArray(a) ? a : [])
       } catch {
         if (!cancelled) setActivities([])
diff --git a/frontend/src/pages/Dashboard.jsx b/frontend/src/pages/Dashboard.jsx
index f8b4dd8..0996931 100644
--- a/frontend/src/pages/Dashboard.jsx
+++ b/frontend/src/pages/Dashboard.jsx
@@ -276,7 +276,7 @@ export default function Dashboard() {
     api.listCaliper(3),
     api.listCirc(2),
     api.listNutrition(30),
-    api.listActivity(30),
+    api.listActivity(800, 30),
     api.latestInsights(),
   ]).then(([s,w,ca,ci,n,a,ins])=>{
     setStats(s); setWeights(w); setCalipers(ca); setCircs(ci)
diff --git a/frontend/src/pages/History.jsx b/frontend/src/pages/History.jsx
index 108c7b9..c0dc264 100644
--- a/frontend/src/pages/History.jsx
+++ b/frontend/src/pages/History.jsx
@@ -972,7 +972,7 @@ export default function History() {
 
   const loadAll = () => Promise.all([
     api.listWeight(365), api.listCaliper(), api.listCirc(),
-    api.listNutrition(90), api.listActivity(200),
+    api.listNutrition(90), api.listActivity(25_000),
     api.nutritionCorrelations(), api.latestInsights(), api.getProfile(),
     api.listPrompts(),
   ]).then(([w,ca,ci,n,a,corr,ins,p,pr])=>{
@@ -983,7 +983,9 @@ export default function History() {
     setLoading(false)
   })
 
-  useEffect(()=>{ loadAll() },[])
+  useEffect(() => {
+    loadAll()
+  }, [activeProfile?.quality_filter_level])
 
   useEffect(() => {
     const t = location.state?.tab
diff --git a/frontend/src/utils/api.js b/frontend/src/utils/api.js
index ad04e3b..7782195 100644
--- a/frontend/src/utils/api.js
+++ b/frontend/src/utils/api.js
@@ -118,7 +118,12 @@ export const api = {
   deleteCaliper: (id)    => req(`/caliper/${id}`,{method:'DELETE'}),
 
   // Activity
-  listActivity:   (l=200)=> req(`/activity?limit=${l}`),
+  /** @param {number} [limit=200] @param {number} [days] nur Einträge ab HEUTE−days (Kalendertage), backend-filtert */
+  listActivity:   (limit=200, days)=> {
+    const q = new URLSearchParams({ limit: String(limit) })
+    if (days != null && days !== '') q.set('days', String(days))
+    return req(`/activity?${q}`)
+  },
   createActivity: (d)    => req('/activity',json(d)),
   updateActivity: (id,d) => req(`/activity/${id}`,jput(d)),
   deleteActivity: (id)   => req(`/activity/${id}`,{method:'DELETE'}),