7 things you should know about donating blood

Tuesday is World Blood Donor Day, which is dedicated to raising awareness about the need for blood donations everywhere. According to the American Red Cross, someone in the U.S. needs blood every two seconds.

When news spread that 49 people had been killed in a massacre in Orlando on Sunday and dozens more injured, locals rushed to donate. In all, 5,300 people donated to Florida-area blood bank One Blood within 24 hours, and the organization is now scheduling donations several days out.

If you're considering donating blood in your area, here are 7 things you should know.

Don't wait for a tragedy.

The best way to help is to donate before tragedy strikes so the blood is available when it's needed. While the organization expressed gratitude to everyone who stepped up following the tragedy, they were also sure to thank donors who were proactive.

"Those of you who gave in the days prior to the shooting ensured blood was available for the victims on that unimaginable night," the organization wrote in a press release. "Thank you, it is regular, dedicated donors like you who keep the blood supply available."

There's more than one way to donate.

While most people are familiar with the process of a "whole blood" donation, that's not the only way to donate. You can give specific parts of your blood, such as platelets, which are especially helpful for patients undergoing cancer treatments.

Your blood type matters.

It's important to know your blood type because it affects how your blood can be best be used to help others. For example, if you have A+ blood, your platelets are particularly helpful. One Blood's website explains which type of donation is best for your type.

It's also important for a diverse group of blood donors to give so that supply is available for every type, especially if you have a rare blood type.

Make sure you're eligible.

Be sure to check requirements with your blood bank. When you go to donate, you'll be asked questions about eligibility requirements covering everything from where you've traveled to how well you're feeling that morning.

The questions ensure the blood bank is following regulations set in place by the Food and Drug Administration meant to prevent the spread of diseases. The tragedy in Florida has called one of the requirements -- that men must not have had sex without another man in the past year -- into question. Though the shooting happened in a gay nightclub, the regulation prevented some gay men from helping.

That requirement was stricter prior to 2015, when there was a lifetime ban on blood donations from any man who had had sex with another man, but some advocates hope the ban will be lifted altogether after massacre.

Be careful what you eat.

While it might be tempting to treat yourself to a slice of pizza or a burger on the day of a donation, that could wind up being the very reason you're turned away. Foods high in fat can make it impossible to test your blood for infectious diseases, meaning you would be turned away from donating.

The best way to ensure your donation is accepted is to eat a diet of iron-rich foods like fish, especially just before you go to donate.

Don't over-do it.

It might seem like common sense not to sign up for a marathon on the day you donate blood, but it doesn't stop there. Be sure to take care of yourself on the day of your donation by getting plenty of rest and drinking lots of fluids. In fact, the American Red Cross recommends you drink an extra 32 ounces of fluid after donating to reduce your risk of feeling dizzy or weak.

Everyone can help.

The American Red Cross lists ways you can help those in need of blood donations, such as volunteering your time and donating money, even if you can't directly give.