Body

backend/app/api/health.py

@@ -146,6 +146,7 @@ async def intraday_health(
     return {
         "hr_values":          metric.intraday_hr if metric else None,
         "body_battery":       metric.body_battery if metric else None,
+        "body_battery_hires": metric.body_battery_hires if metric else None,
     }
 
 

backend/app/models/user.py

@@ -246,6 +246,7 @@ class HealthMetric(Base):
     spo2_avg = Column(Float, nullable=True)
     intraday_hr = Column(JSON, nullable=True)           # [[epoch_ms, bpm], ...] — not in API list response
     body_battery = Column(JSON, nullable=True)          # {charged,drained,start_level,end_level,values:[[ts_ms,level,type,stress]...]}
+    body_battery_hires = Column(JSON, nullable=True)    # [[ts_ms, level], ...] interpolated from bb + HR; higher resolution than raw values
 
     __table_args__ = (
         UniqueConstraint("user_id", "date", name="uq_health_user_date"),

backend/app/services/garmin_connect_sync.py

@@ -258,12 +258,19 @@ def sync_wellness(garmin, user_id: int, since: Optional[datetime], db,
                 row["body_battery"] = _json.dumps(bb)
 
         # Intraday heart rate — store non-null [epoch_ms, bpm] pairs
+        intraday = None
         if hr_raw:
             raw_vals = hr_raw.get("heartRateValues") or []
             intraday = [[int(ts), int(v)] for ts, v in raw_vals if v is not None]
             if intraday:
                 row["intraday_hr"] = intraday
 
+        # High-resolution body battery derived from BB checkpoints + intraday HR
+        if bb and intraday:
+            hires = _compute_body_battery_hires(bb.get("values") or [], intraday)
+            if hires:
+                row["body_battery_hires"] = _json.dumps(hires)
+
         if not row:
             continue
 
@@ -351,6 +358,72 @@ def _parse_body_battery(bb_response, day_str: str):
     }
 
 
+def _compute_body_battery_hires(bb_values, intraday_hr):
+    """
+    Produce a higher-resolution body battery series by interpolating between
+    sparse BB checkpoints using intraday HR as a proxy for effort.
+
+    During drain segments (BB falling) the drain is distributed proportionally
+    to how much each HR reading exceeds the day's median — peaks spend battery
+    faster than valleys.  During recovery segments (BB rising) recovery is
+    spread uniformly over time.
+
+    Returns [[ts_ms, level], ...] at the granularity of intraday HR, or None
+    if inputs are insufficient.
+    """
+    if not bb_values or not intraday_hr or len(bb_values) < 2:
+        return None
+
+    bb  = sorted(bb_values,  key=lambda x: x[0])
+    hr  = sorted(intraday_hr, key=lambda x: x[0])
+
+    hr_vals = [bpm for _, bpm in hr if bpm is not None and bpm > 0]
+    if not hr_vals:
+        return None
+
+    hr_median = sorted(hr_vals)[len(hr_vals) // 2]
+
+    result = []
+    for i in range(len(bb) - 1):
+        t1, L1 = bb[i][0], bb[i][1]
+        t2, L2 = bb[i + 1][0], bb[i + 1][1]
+        delta = L2 - L1
+
+        seg_hr = [(ts, bpm) for ts, bpm in hr if t1 <= ts <= t2 and bpm is not None]
+        result.append([t1, round(float(L1), 1)])
+
+        if not seg_hr or abs(delta) < 1:
+            continue
+
+        if delta < 0:
+            # Drain: weight each reading by HR above median
+            efforts = [max(0.0, bpm - hr_median) for _, bpm in seg_hr]
+            total   = sum(efforts) or 1.0
+            cumul   = 0.0
+            for j, (ts, bpm) in enumerate(seg_hr):
+                cumul += efforts[j] * delta / total
+                level  = max(0.0, min(100.0, L1 + cumul))
+                result.append([ts, round(level, 1)])
+        else:
+            # Recovery: linear over time
+            span = max(1, t2 - t1)
+            for ts, _ in seg_hr:
+                frac  = (ts - t1) / span
+                level = max(0.0, min(100.0, L1 + delta * frac))
+                result.append([ts, round(level, 1)])
+
+    result.append([bb[-1][0], round(float(bb[-1][1]), 1)])
+
+    # Deduplicate and sort
+    seen, out = set(), []
+    for item in sorted(result, key=lambda x: x[0]):
+        if item[0] not in seen:
+            seen.add(item[0])
+            out.append(item)
+
+    return out if len(out) > 4 else None
+
+
 def _safe(fn, *args):
     try:
         return fn(*args)

frontend/src/components/activity/MetricTimeline.jsx

@@ -100,7 +100,7 @@ export default function MetricTimeline({ dataPoints, activeMetrics, metrics, onH
               {metric.unit && <span className="text-xs text-gray-600">({metric.unit})</span>}
             </div>
             <ResponsiveContainer width="100%" height={100}>
-              <ComposedChart data={chartData} margin={{ top: 2, right: 8, bottom: 2, left: 8 }}>
+              <ComposedChart data={chartData} margin={{ top: 2, right: 8, bottom: 2, left: 8 }} syncId="activity-metrics">
                 <CartesianGrid strokeDasharray="3 3" stroke="#1f2937" vertical={false} />
                 <XAxis
                   dataKey="distance_m"

frontend/src/pages/HealthPage.jsx

@@ -71,19 +71,31 @@ function bbLevelColor(level) {
   return '#ef4444'
 }
 
-function BodyBatteryChart({ bb }) {
+function BodyBatteryChart({ bb, hiresValues }) {
   if (!bb) return null
   const { charged, drained, start_level, end_level, values } = bb
   if (!values?.length && end_level == null) return null
 
-  const chartData = (values || []).map(([ts, level, type]) => ({
-    t: ts,
-    level,
-    type: type ?? 4,
-    bar: 100,
+  // Background bars use the raw checkpoint type codes to colour activity segments.
+  const bgData = (values || []).map(([ts, , type]) => ({ t: ts, type: type ?? 4, bar: 100 }))
+
+  // Line uses hi-res data when available, otherwise the raw checkpoints.
+  const lineData = hiresValues?.length
+    ? hiresValues.map(([ts, level]) => ({ t: ts, level }))
+    : (values || []).map(([ts, level]) => ({ t: ts, level }))
+
+  // Merge into a single dataset keyed by timestamp so both series share the same XAxis.
+  const tsSet = new Set([...bgData.map(d => d.t), ...lineData.map(d => d.t)])
+  const bgMap   = Object.fromEntries(bgData.map(d => [d.t, d]))
+  const lineMap = Object.fromEntries(lineData.map(d => [d.t, d]))
+  const chartData = [...tsSet].sort((a, b) => a - b).map(t => ({
+    t,
+    bar:   bgMap[t]?.bar   ?? null,
+    type:  bgMap[t]?.type  ?? null,
+    level: lineMap[t]?.level ?? null,
   }))
 
-  const presentTypes = [...new Set(chartData.map(d => d.type))]
+  const presentTypes = [...new Set(bgData.map(d => d.type))]
   const levelColor = bbLevelColor(end_level)
 
   return (
@@ -113,12 +125,13 @@ function BodyBatteryChart({ bb }) {
                 <XAxis dataKey="t" tick={{ fontSize: 9, fill: '#6b7280' }} axisLine={false} tickLine={false}
                   tickFormatter={ts => format(new Date(ts), 'HH:mm')}
                   interval={Math.max(1, Math.floor(chartData.length / 6))} />
+                <YAxis domain={[0, 100]} hide />
                 <Tooltip contentStyle={tooltipStyle}
                   labelFormatter={ts => format(new Date(ts), 'HH:mm')}
                   formatter={(v, name) => name === 'level' ? [`${Math.round(v)}`, 'Battery'] : null} />
                 <Bar dataKey="bar" isAnimationActive={false} maxBarSize={6}>
                   {chartData.map((d, i) => (
-                    <Cell key={i} fill={BB_TYPE_COLOR[d.type] ?? '#374151'} fillOpacity={0.8} />
+                    <Cell key={i} fill={d.type != null ? (BB_TYPE_COLOR[d.type] ?? '#374151') : 'transparent'} fillOpacity={0.8} />
                   ))}
                 </Bar>
                 <Line type="monotone" dataKey="level" stroke="#e5e7eb" strokeWidth={1.5}
@@ -180,7 +193,7 @@ function NavArrow({ onClick, disabled, children }) {
   )
 }
 
-function DailySnapshot({ day, avg30, intradayHr, bodyBattery, onOlder, onNewer, hasOlder, hasNewer }) {
+function DailySnapshot({ day, avg30, intradayHr, bodyBattery, bbHires, onOlder, onNewer, hasOlder, hasNewer }) {
   if (!day) return (
     <div className="text-center py-10 text-gray-600">
       <p className="text-3xl mb-2">📊</p>
@@ -334,7 +347,7 @@ function DailySnapshot({ day, avg30, intradayHr, bodyBattery, onOlder, onNewer,
               </div>
             </div>
           )}
-          <BodyBatteryChart bb={bodyBattery} />
+          <BodyBatteryChart bb={bodyBattery} hiresValues={bbHires} />
         </div>
       )}
 
@@ -580,6 +593,7 @@ export default function HealthPage() {
         avg30={summary?.avg_30d}
         intradayHr={intradayData?.hr_values}
         bodyBattery={intradayData?.body_battery}
+        bbHires={intradayData?.body_battery_hires}
         onOlder={goOlder}
         onNewer={goNewer}
         hasOlder={selectedIdx >= 0 && selectedIdx < allDaysSorted.length - 1}