diff --git a/engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/activity/ActivityExecutor.java b/engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/activity/ActivityExecutor.java
index e047374ff..d494b1480 100644
--- a/engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/activity/ActivityExecutor.java
+++ b/engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/activity/ActivityExecutor.java
@@ -15,6 +15,9 @@
  */
 package io.nosqlbench.engine.core.lifecycle.activity;
 
+import com.codahale.metrics.Gauge;
+import io.nosqlbench.api.engine.metrics.ActivityMetrics;
+import io.nosqlbench.api.engine.metrics.instruments.NBFunctionGauge;
 import io.nosqlbench.api.labels.NBLabeledElement;
 import io.nosqlbench.api.labels.NBLabels;
 import io.nosqlbench.engine.api.activityapi.core.*;
@@ -72,6 +75,7 @@ public class ActivityExecutor implements NBLabeledElement, ActivityController, P
     private long stoppedAt = 0L;
 
     private ActivityExecutorShutdownHook shutdownHook = null;
+    private NBFunctionGauge threadsGauge;
 
     public ActivityExecutor(Activity activity, String sessionId) {
         this.activity = activity;
@@ -450,6 +454,15 @@ public class ActivityExecutor implements NBLabeledElement, ActivityController, P
         startMotorExecutorService();
         startRunningActivityThreads();
         awaitMotorsAtLeastRunning();
+        registerMetrics();
+    }
+
+    private void registerMetrics() {
+        this.threadsGauge= threadsGauge = ActivityMetrics.register(new NBFunctionGauge(activity, () -> (double) this.motors.size(), "threads"));
+    }
+    private void unregisterMetrics() {
+        ActivityMetrics.unregister(this.threadsGauge);
+        this.threadsGauge=null;
     }
 
     private boolean shutdownExecutorService(int secondsToWait) {
@@ -472,6 +485,7 @@ public class ActivityExecutor implements NBLabeledElement, ActivityController, P
         } finally {
             logger.trace(() -> "finally shutting down activity " + this.getActivity().getAlias());
             this.stoppedAt = System.currentTimeMillis();
+            unregisterMetrics();
             activity.setRunState(RunState.Stopped);
         }
 
@@ -567,6 +581,16 @@ public class ActivityExecutor implements NBLabeledElement, ActivityController, P
             .build());
     }
 
+    private class ThreadsGauge implements Gauge<Double> {
+        public ThreadsGauge(ActivityExecutor activityExecutor) {
+            ActivityExecutor ae = activityExecutor;
+        }
+
+        @Override
+        public Double getValue() {
+            return (double) ActivityExecutor.this.motors.size();
+        }
+    }
 }