Indices trading is considered a relatively secure form of trading, especially for a long-term investment, as you are spreading your risk across an entire segment of stocks as opposed to a single stock.
However, some volatility risk still remains. Stock indices can go up or down for a variety of reasons. But unfavorable price moves can lead to losses, especially if you cannot react to a price change immediately.
Collecting news and analysis will help you to make better decisions. It is also a good idea to use risk-management tools. Choosing tools such as Stop Losses, Limit Orders, and Trailing Stops will help you to protect yourself from volatility.