diff --git a/lisp/ob-lua.el b/lisp/ob-lua.el
index dd02d6aee..64d15f75c 100644
--- a/lisp/ob-lua.el
+++ b/lisp/ob-lua.el
@@ -335,7 +335,7 @@ PREAMBLE string is appended to BODY."
 If RESULT-TYPE equals `output' then return standard output as a
 string.  If RESULT-TYPE equals `value' then return the value of the
 last statement in BODY, as elisp."
-  (let* ((send-wait (lambda () (comint-send-input nil t) (sleep-for 0 5)))
+  (let* ((send-wait (lambda () (comint-send-input nil t) (sleep-for 0.005)))
 	 (dump-last-value
 	  (lambda
 	    (tmp-file pp)
diff --git a/lisp/ob-python.el b/lisp/ob-python.el
index d6bc10eee..6c568a36d 100644
--- a/lisp/ob-python.el
+++ b/lisp/ob-python.el
@@ -280,7 +280,7 @@ then create.  Return the initialized session."
       ;; multiple prompts during initialization.
       (with-current-buffer py-buffer
         (while (not org-babel-python--initialized)
-          (sleep-for 0 10)))
+          (sleep-for 0.010)))
       (setq org-babel-python-buffers
 	    (cons (cons session py-buffer)
 		  (assq-delete-all session org-babel-python-buffers)))
@@ -435,7 +435,7 @@ with open('%s') as f:
 		      (body (org-babel-python-format-session-value
 			     tmp-src-file results-file result-params)))
 		 (org-babel-python-send-string session body)
-		 (sleep-for 0 10)
+		 (sleep-for 0.010)
 		 (org-babel-eval-read-file results-file)))))))
     (org-babel-result-cond result-params
       results
diff --git a/testing/lisp/test-ob-R.el b/testing/lisp/test-ob-R.el
index 192c9f33b..9ffbf3afd 100644
--- a/testing/lisp/test-ob-R.el
+++ b/testing/lisp/test-ob-R.el
@@ -174,7 +174,7 @@ log10(10)
 	       (and (not (string= expected (org-babel-execute-src-block)))
 		    (string= expected
 			     (progn
-			       (sleep-for 0 200)
+			       (sleep-for 0.200)
 			       (goto-char (org-babel-where-is-src-block-result))
 			       (org-babel-read-result)))))))))
 
@@ -191,7 +191,7 @@ log10(10)
 	       (and (not (string= expected (org-babel-execute-src-block)))
 		    (string= expected
 			     (progn
-			       (sleep-for 0 200)
+			       (sleep-for 0.200)
 			       (goto-char (org-babel-where-is-src-block-result))
 			       (org-babel-read-result)))))))))
 
@@ -208,7 +208,7 @@ log10(10)
     (org-test-with-temp-text
      (concat src-block results-before)
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block results-after)
                              (buffer-string)))))))
 
@@ -223,7 +223,7 @@ log10(10)
     (org-test-with-temp-text
      (concat src-block results-before)
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block results-after)
                              (buffer-string)))))))
 
@@ -239,7 +239,7 @@ log10(10)
     (org-test-with-temp-text
      src-block
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block result)
                              (buffer-string)))))))
 
@@ -253,7 +253,7 @@ log10(10)
     (org-test-with-temp-text
      src-block
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block result)
                              (buffer-string)))))))
 
@@ -268,7 +268,7 @@ log10(10)
     (org-test-with-temp-text
      src-block
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block result)
                              (buffer-string)))))))
 
@@ -312,7 +312,7 @@ x
   (org-babel-next-src-block)
   (should (progn  
             (org-babel-execute-src-block)
-            (sleep-for 0 200)
+            (sleep-for 0.200)
             (string= (concat text result)
                      (buffer-string)))))))
 
diff --git a/testing/lisp/test-ob-julia.el b/testing/lisp/test-ob-julia.el
index e2ec922a2..f5666a93a 100644
--- a/testing/lisp/test-ob-julia.el
+++ b/testing/lisp/test-ob-julia.el
@@ -224,7 +224,7 @@ print('Yep!')
 	       (and (not (string= expected (org-babel-execute-src-block)))
 		    (string= expected
 			     (progn
-			       (sleep-for 0 200)
+			       (sleep-for 0.200)
 			       (goto-char (org-babel-where-is-src-block-result))
 			       (org-babel-read-result)))))))))
 
@@ -248,7 +248,7 @@ print(\"Yep!\")
     (org-test-with-temp-text
      (concat src-block results-before)
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block results-after)
                              (buffer-string)))))))
 
@@ -268,7 +268,7 @@ print(list(range(3)))
     (org-test-with-temp-text
      src-block
      (should (progn (org-babel-execute-src-block)
-                    (sleep-for 0 200)
+                    (sleep-for 0.200)
                     (string= (concat src-block result)
                              (buffer-string)))))))
 
diff --git a/testing/lisp/test-ob-python.el b/testing/lisp/test-ob-python.el
index c11e1d0c2..18861444e 100644
--- a/testing/lisp/test-ob-python.el
+++ b/testing/lisp/test-ob-python.el
@@ -242,7 +242,7 @@ print('Yep!')
 	        (and (not (string= expected (org-babel-execute-src-block)))
 		     (string= expected
 			      (progn
-			        (sleep-for 0 200)
+			        (sleep-for 0.200)
 			        (goto-char (org-babel-where-is-src-block-result))
 			        (org-babel-read-result)))))))))
 
@@ -269,7 +269,7 @@ print(\"Yep!\")
     (org-test-with-temp-text
         (concat src-block results-before)
       (should (progn (org-babel-execute-src-block)
-                     (sleep-for 0 200)
+                     (sleep-for 0.200)
                      (string= (concat src-block results-after)
                               (buffer-string)))))))
 
@@ -292,7 +292,7 @@ print(list(range(3)))
     (org-test-with-temp-text
         src-block
       (should (progn (org-babel-execute-src-block)
-                     (sleep-for 0 200)
+                     (sleep-for 0.200)
                      (string= (concat src-block result)
                               (buffer-string)))))))