diff --git a/subscriber.go b/subscriber.go
index 44560d7..80d3587 100644
--- a/subscriber.go
+++ b/subscriber.go
@@ -105,11 +105,13 @@ func (s *subscriber) poll(ctx context.Context) {
 					continue
 				}
 
+				s.Lock()
 				for tp := range s.consumers {
 					if v, ok := lmap[tp.p]; ok {
 						s.kopts.Meter.Counter(semconv.BrokerGroupLag, "topic", s.topic, "group", s.opts.Group, "partition", strconv.Itoa(int(tp.p)), "lag", strconv.Itoa(int(v.Lag)))
 					}
 				}
+				s.Unlock()
 
 			}
 		}