diff --git a/src/qibolab/sequence.py b/src/qibolab/sequence.py
index b72dd6a74..fd9f89e2c 100644
--- a/src/qibolab/sequence.py
+++ b/src/qibolab/sequence.py
@@ -82,11 +82,11 @@ def channel(self, channel: ChannelId) -> Iterable[PulseLike]:
 
     def channel_duration(self, channel: ChannelId) -> float:
         """Duration of the given channel."""
-        sequence = self
-        for _, pulse in self:
-            if isinstance(pulse, Align):
-                sequence = self.align_to_delays()
-                break
+        sequence = (
+            self.align_to_delays()
+            if any(isinstance(pulse, Align) for _, pulse in self)
+            else self
+        )
         return sum(pulse.duration for pulse in sequence.channel(channel))
 
     def pulse_channels(self, pulse_id: int) -> list[ChannelId]: