Waterfalls are a wonder of nature. They are often the prizes found after a long hike through the woods. Waterfalls are a worldwide phenomenon. However, the number of waterfalls are not easy to determine due to differing definitions; California is estimated to have as many as 400. The world’s longest waterfall is Angel Falls in Venezuela at 3212 feet; the tallest waterfall in the US is Yosemite Falls at 2425 feet. Victoria Falls in Zimbabwe is felt to be the largest at 5604 feet wide and 304 feet high. Its roar can be heard 25 miles away!  Waterfalls are nice to look at, but if you live near one would the constant roar of the water be soothing or annoying?

Sound is measured in decibels.  Decibels for some common sounds include normal conversation which is 60 decibels, whispering is 20 decibels, and a rock concert is 110 decibels. Constant exposure (more than 8 hours a day) to sounds over 85 decibels is considered hazardous and unhealthy. Noise is sound that is perceived as annoying.  Noise pollution, or environmental noise, is noise that affects a person’s health or behavior.  Many studies have shown that environmental pollution in the form of traffic noise (from cars, airplanes or trains) is associated with heart disease. Traffic noise confers an increased risk for high blood pressure, heart attack, stroke, atrial fibrillation and congestive heart failure.  Constant traffic noise increases the risk for high blood pressure starting at 45 decibels and increases every 5 decibels. Heart artery disease starts to occur with continued exposure to noise at 50 decibels and increases each 5 decibels in the evening and 10 decibels at night. The constant annoyance of traffic noise causes a stress reaction. It disturbs sleep, increases adrenaline, releases stress hormones, raises blood pressure and alters blood sugar and cholesterol metabolism. The effect is stronger if the noise occurs at night. Nighttime aircraft noise increases blood pressure further and heart disease is more strongly associated with people whose bedrooms face the road.   Unfortunately, noise pollution often goes hand in hand with air pollution. It may be difficult to determine which is the cause for heart disease: noise or air pollutants. There are other circumstances where noise may be implicated in heart disease. People who have long-term exposure to loud noise at work are two times more likely to have heart artery disease.  The intensive care unit (ICU) is another area where noise pollution is a factor. ICUs are noisy places; alarms go off, IV pumps beep and there is 24 hour per day chatter among the ICU personnel. The noise level in ICUs is a constant 50 to 75 decibels, even at night. Thus, sleep disturbance is a common problem for ICU patients. In addition, noise pollution in the ICU is associated with delirium (confusion) and worse outcomes among patients. 

Not all sound is bad for the heart. Music and sounds from nature may be beneficial for the heart. Listening to music may help heart patients by decreasing heart rate and blood pressure, relaxing arteries and improving blood flow and reducing stress. For example, patients who listened to music after heart surgery had less pain and less anxiety.   Music, however, is very personal; what one person perceives as soothing, another may find annoying.  Despite that, neuroscientists were able to test a number of songs on their ability to reduce anxiety. Their research produced a playlist of the most relaxing songs on earth.  Are nature sounds just as soothing as music? Not much is known about sounds found in nature. One group had patients undergoing heart bypass surgery listen to nature sounds (birds chirping, waves on the beach, jungle sounds and the sound of rain).  They found that natural sounds were able to reduce anxiety in patients around the time of surgery. 

So, are waterfalls soothing sounds from nature or noise pollution?  Consider the case of Niagara Falls, New York, one of the largest waterfalls in the world and one whose noise level is a constant 95 decibels.  According to an article in the Buffalo News from December 2016, the Buffalo Niagara area has one of the highest rates of heart attacks in the country.  There may be many reasons for that, but could it be from noise pollution from the Falls?  More research is needed on this question, but if you are planning to visit, consider bringing your noise cancelling headphones.