diff --git a/inc/Classes.php b/inc/Classes.php
index f0ebf90..b7e05a9 100644
--- a/inc/Classes.php
+++ b/inc/Classes.php
@@ -15,8 +15,8 @@
           ON s.id = u_s.subject_id
         ' : '').
         'WHERE
-          c.begins < NOW() AND
-          c.ends > NOW()'.($isSignedIn ? ' AND
+          c.begins < UNIX_TIMESTAMP() AND
+          c.ends > UNIX_TIMESTAMP()'.($isSignedIn ? ' AND
           (
             u_s.user_id = :user_id OR
             u_s.subject_id IS NULL
diff --git a/utils/db_structure.sql b/utils/db_structure.sql
index b22a6dd..64837a6 100644
--- a/utils/db_structure.sql
+++ b/utils/db_structure.sql
@@ -29,9 +29,9 @@
   calendar_name VARCHAR(100) NOT NULL,
   INDEX(calendar_name),
   room VARCHAR(10) NOT NULL,
-  begins DATETIME NOT NULL,
+  begins INT NOT NULL, -- UNIX timestamp de l'hora d'inici
   INDEX(begins),
-  ends DATETIME NOT NULL,
+  ends INT NOT NULL, -- UNIX timestamp de l'hora de fi
   INDEX(ends)
 );