Lag spikes are generally caused by interruptions to your network, and while they resolve quickly, could have a direct effect on your response time when gaming online.
Factors that can contribute to ping spikes and packet loss are:
- Broadband connection speed
- Connection through Wi-Fi vs cable/ethernet connection
- Network Congestion
- Problems with Hardware
- Apps running in the background
- Quality of the connection delivered from the Internet Service Provider (ISP)
- Inadequate Bandwidth
- Geological Location
Read more about ping spikes and how you can optimise your connection here.