diff --git a/phys2denoise/metrics/cardiac.py b/phys2denoise/metrics/cardiac.py
index f52d7b2..b8b2dcc 100644
--- a/phys2denoise/metrics/cardiac.py
+++ b/phys2denoise/metrics/cardiac.py
@@ -53,7 +53,7 @@ def _crf(t):
 
     dt = tr / oversampling
     time_stamps = np.linspace(
-        0, time_length, np.rint(float(time_length) / dt).astype(np.int)
+        0, time_length, np.rint(float(time_length) / dt).astype(int)
     )
     time_stamps -= onset
     crf_arr = _crf(time_stamps)
diff --git a/phys2denoise/metrics/chest_belt.py b/phys2denoise/metrics/chest_belt.py
index 85be77c..9417e67 100644
--- a/phys2denoise/metrics/chest_belt.py
+++ b/phys2denoise/metrics/chest_belt.py
@@ -162,7 +162,7 @@ def env(resp, samplerate, window=10):
 
 
 @due.dcite(references.CHANG_GLOVER_2009)
-def rv(resp, samplerate, window=6, lags=(0,)):
+def rv(resp, samplerate, window=6):
     """Calculate respiratory variance.
 
     Parameters
@@ -260,7 +260,7 @@ def _rrf(t):
 
     dt = tr / oversampling
     time_stamps = np.linspace(
-        0, time_length, np.rint(float(time_length) / dt).astype(np.int)
+        0, time_length, np.rint(float(time_length) / dt).astype(int)
     )
     time_stamps -= onset
     rrf_arr = _rrf(time_stamps)
diff --git a/phys2denoise/metrics/utils.py b/phys2denoise/metrics/utils.py
index 7426a5c..9d41e77 100644
--- a/phys2denoise/metrics/utils.py
+++ b/phys2denoise/metrics/utils.py
@@ -116,9 +116,9 @@ def apply_lags(arr1d, lags):
     arr_with_lags = np.zeros((arr1d.shape[0], len(lags)))
     for i_lag, lag in enumerate(lags):
         if lag < 0:
-            arr_delayed = np.hstack((arr1d[lag:], np.zeros(lag)))
+            arr_delayed = np.hstack((arr1d[abs(lag):], np.zeros(abs(lag))))
         elif lag > 0:
-            arr_delayed = np.hstack((np.zeros(lag), arr1d[lag:]))
+            arr_delayed = np.hstack((np.zeros(lag), arr1d[:-lag]))
         else:
             arr_delayed = arr1d.copy()
         arr_with_lags[:, i_lag] = arr_delayed