So you haven’t gotten around to donating blood or getting on the bone marrow transplant list or taking a class on CPR. It’s time to step up, people. Fortunately for you, you can cross the last one off the list, sort of. The American Heart Association is letting everybody know that even if you aren’t trained in CPR, jumping in and administering chest compressions if you witness an adult collapse after having a heart attack is more than twice as likely to save his life than just calling 911 alone.

You don’t need to worry if you aren’t familiar with mouth-to-mouth resuscitation—chest compressions alone have proven to be nearly as effective if they are started immediately. Aim for pushing hard and fast in the middle of the chest at a rate of about 100 time per minute. You don’t want to do this if the collapse is the result of an overdose or drowning; for that you’ll need rescue breathing. Still, if you really want to be the hero this summer at the beach, take the CPR class.