That sentence looks like the start of a headline or hook, but it needs the last word to make sense. Here are common, ready-to-use completions depending on what you mean:
Health / lifestyle headlines
- These are the consequences of sleeping with a fan on
- These are the consequences of sleeping with a mobile phone next to you
- These are the consequences of sleeping with a light on
- These are the consequences of sleeping with wet hair
- These are the consequences of sleeping with a TV on
More neutral / informative tone
- These are the possible effects of sleeping with a fan on overnight
- These are the risks associated with sleeping with your phone nearby
If you tell me what the “a” refers to, I can:
- finish the sentence precisely,
- rewrite it as a click-worthy headline,
- or turn it into a short health explainer.