diff --git a/src/DebugBar/DebugBar.php b/src/DebugBar/DebugBar.php
index b3999b47..982265e6 100644
--- a/src/DebugBar/DebugBar.php
+++ b/src/DebugBar/DebugBar.php
@@ -234,10 +234,25 @@ public function collect()
             )
         );
 
+        // The RequestDataCollector stores a copy of the session data and the
+        // session stores the collected data when it gets stacked. This leads
+        // to exponential memory usage growth if multiple requests have
+        // their data stacked before the stacked data is rendered. We can avoid
+        // that by temporarily removing the stacked data from the session.
+        $http = $this->getHttpDriver();
+        if ($http->isSessionStarted()) {
+            $stack = $http->getSessionValue($this->stackSessionNamespace);
+            $http->deleteSessionValue($this->stackSessionNamespace);
+        }
+
         foreach ($this->collectors as $name => $collector) {
             $this->data[$name] = $collector->collect();
         }
 
+        if ($http->isSessionStarted()) {
+            $http->setSessionValue($this->stackSessionNamespace, $stack);
+        }
+
         // Remove all invalid (non UTF-8) characters
         array_walk_recursive($this->data, function (&$item) {
                 if (is_string($item) && !mb_check_encoding($item, 'UTF-8')) {