Emotional stress
If you are wondering how exactly emotional stress can cause hiccups, here is how. When you are stressed emotionally, your body tries to make up for it over time by producing more oxygen to perform its activities. However, you can take in the air suddenly in that process, which your diaphragm will react to, eventually causing you to have hiccups. If you notice that you are getting hiccups more frequently than usual, it is important to watch your stress level, because stress is a huge trigger for hiccups.