How often do you check your email? If you're like 60.4% of knowledge workers, it's every 8 minutes or faster. Seems too fast? Roy Maurer digs into the patterns and how to reduce digital distractions at work. The tl;dr:
Productivity experts suggest prioritizing and batching communication into specific blocks during the day or scheduling periods of focused work without e-mail or Slack check-ins during parts of the day. — Roy Maurer
Update your tools to filter out unimportant messages for later. Also, consider using pomodoro technique to maintain a high focus on work. Also, don't be afraid to quit Slack or email then open it up later.