diff --git a/test/core/gpr/arena_test.cc b/test/core/gpr/arena_test.cc
index 111414e..3e7c906 100644
--- a/test/core/gpr/arena_test.cc
+++ b/test/core/gpr/arena_test.cc
@@ -71,7 +71,7 @@
   static const size_t allocs_##name[] = {__VA_ARGS__}; \
   test(#name, init_size, allocs_##name, GPR_ARRAY_SIZE(allocs_##name))
 
-#define CONCURRENT_TEST_THREADS 100
+#define CONCURRENT_TEST_THREADS 10
 
 size_t concurrent_test_iterations() {
   if (sizeof(void*) < 8) return 1000;