diff --git a/specs/altair/beacon-chain.md b/specs/altair/beacon-chain.md
index 33ef9a12b..41b86f3ac 100644
--- a/specs/altair/beacon-chain.md
+++ b/specs/altair/beacon-chain.md
@@ -579,7 +579,7 @@ def process_sync_committee(state: BeaconState, aggregate: SyncAggregate) -> None
     # Apply participant and proposer rewards
     all_pubkeys = [v.pubkey for v in state.validators]
     committee_indices = [ValidatorIndex(all_pubkeys.index(pubkey)) for pubkey in state.current_sync_committee.pubkeys]
-    for index, participation_bit in zip(committee_indices, aggregate.sync_committee_bits):
+    for participant_index, participation_bit in zip(committee_indices, aggregate.sync_committee_bits):
         if participation_bit:
             increase_balance(state, participant_index, participant_reward)
             increase_balance(state, get_beacon_proposer_index(state), proposer_reward)