diff --git a/README.md b/README.md
index 86b41c0..915f7b4 100644
--- a/README.md
+++ b/README.md
@@ -310,7 +310,7 @@ be cleared every time the program is run
 When parsing long feeds, with a lot of items (100+), morss might take a lot of
 time to parse it, or might even run into a memory overflow on some shared
 hosting plans (limits around 10Mb), in which case you might want to adjust the
-different values at the top of the script.
+below settings via environment variables.
 
 - `MAX_TIME` sets the maximum amount of time spent *fetching* articles, more time might be spent taking older articles from cache. `-1` for unlimited.
 - `MAX_ITEM` sets the maximum number of articles to fetch. `-1` for unlimited. More articles will be taken from cache following the nexts settings.
diff --git a/morss/morss.py b/morss/morss.py
index e6ffd74..a4f2502 100644
--- a/morss/morss.py
+++ b/morss/morss.py
@@ -24,14 +24,15 @@ except ImportError:
     from http.client import HTTPException
     from urllib.parse import urlparse, urljoin, parse_qs
 
-MAX_ITEM = 5  # cache-only beyond
-MAX_TIME = 2  # cache-only after (in sec)
 
-LIM_ITEM = 10  # deletes what's beyond
-LIM_TIME = 2.5  # deletes what's after
+MAX_ITEM = int(os.getenv('MAX_ITEM', 5)) # cache-only beyond
+MAX_TIME = int(os.getenv('MAX_TIME', 2)) # cache-only after (in sec)
 
-DELAY = 10 * 60  # xml cache & ETag cache (in sec)
-TIMEOUT = 4  # http timeout (in sec)
+LIM_ITEM = int(os.getenv('LIM_ITEM', 10)) # deletes what's beyond
+LIM_TIME = int(os.getenv('LIM_TIME', 2.5)) # deletes what's after
+
+DELAY = int(os.getenv('DELAY', 10 * 60)) # xml cache & ETag cache (in sec)
+TIMEOUT = int(os.getenv('TIMEOUT', 4)) # http timeout (in sec)
 
 
 class MorssException(Exception):