Bitcoin is constantly going up and down in value.
If BTC takes a large dip below or is on a massive rise above the price you purchased at, you can pause the lending on the lending offers page and flip the offer's status to paused. See image below.
The majority of the loans are made within 2 hours of the deposit. It is unlikely you will lose or gain much value during that time. Still, it is wise to keep an eye on the value of BTC during that time.
There are many methods of tracking BTC's value. You can track it on the NYSE at INDEXNYSEGIS:NYXBT, you can use a nice widget on Android from Drakdoo that will allow you to set price alerts, you can also check on many websites such as Bitcoin.com and you can even Google it.