Today is the fourth day of New Jersey’s second summer heat wave, and some doctors say it gets worse with each passing day.

There is a heat advisory in effect for the state from today and through Tuesday due to feel-like temperatures reaching 95-100 degrees for these two days. Although the actual air temperatures are in the 90s, it’s the heat index and humidity that makes things worse, especially if you are a heart or lung patient.

MORE: News 12 local forecast report

Dr. Eric Costanzo, an ICU director and pulmonologist at Jersey Shore University Medical Center, says focusing on the heat index is important because that really is going to “guide how rapidly you dehydrate your preparation for the day if you have chronic illnesses like cardiovascular pulmonary issues, things that you may want to stay inside in an air conditioning environment because of that heat index.”

Costanzo also says there's no getting “used to” the heat in New Jersey. In fact, it’s quite the opposite. With each passing day, he says residents should monitor the forecasted heat index temperatures closely — and if you can, take advantage of a day by the ocean in the sea breeze or stay inside.

Costanzo’s recommendations include: