diff --git a/src/components/WorkoutPlot.tsx b/src/components/WorkoutPlot.tsx
index 6c15ece..d0d1cf3 100644
--- a/src/components/WorkoutPlot.tsx
+++ b/src/components/WorkoutPlot.tsx
@@ -24,7 +24,7 @@ export const WorkoutPlot: React.FC<{ intervals: Interval[] }> = ({ intervals })
 
   return (
     <Plot>
-      { intervals.map((interval) => toBarProps(interval, workoutDuration, maxIntensity)).map((props) => (<Bar {...props} />)) }
+      { intervals.map((interval) => toBarProps(interval, workoutDuration, maxIntensity)).map((props, i) => (<Bar key={i} {...props} />)) }
     </Plot>
   );
 }
diff --git a/src/components/WorkoutStats.tsx b/src/components/WorkoutStats.tsx
index 15e2c9f..85924ed 100644
--- a/src/components/WorkoutStats.tsx
+++ b/src/components/WorkoutStats.tsx
@@ -53,7 +53,7 @@ export const WorkoutStats: React.FC<{workout: Workout}> = ({ workout }) => {
       <Section>
         <Header>Zone distribution</Header>
         <ZoneList>
-          {zones.map(zone => (<StatsLine label={zone.name} value={formatDuration(zone.duration)} />)) }
+          {zones.map(zone => (<StatsLine key={zone.name} label={zone.name} value={formatDuration(zone.duration)} />)) }
         </ZoneList>
       </Section>
     </Container>