How often should you apply an ice pack to an injured leg? question 18 options: every hour for 5 minutes at a time for the first 36 hours. every 5–6 hours for 10 minutes at a time for the first 24 hours. every 2 or 3 hours for 20–30 minutes at a time for the first 24–48 hours. every 30 minutes for 5 minutes at a time for the first 5 hours.