Month: November 2022

Heavy rains and sea level rise contribute to major flooding events that are one effect of climate change. Surging water rushing into buildings often causes immediate harms, such as drowning deaths, injuries sustained while seeking shelter or fleeing, and hypothermia after exposure to cold waters with no shelter or heat.

But long after news trucks leave and public attention moves on, flooding continues to affect communities in visible and less visible ways. Among the less visible threats is a higher risk of respiratory health problems like asthma and allergic reactions. Fortunately, you can take steps to minimize or avoid flooding, or to reduce respiratory health risks after flooding occurs.

How does flooding trigger respiratory health issues?

Flooding may bring water contaminated with toxic chemicals, heavy metals, pesticides, biotoxins, sewage, and water-borne pathogens into buildings. Afterward, some toxic contaminants remain in dried sediments left behind. When disturbed through everyday actions like walking and cleaning, this turns into microscopic airborne dust. Anything in that dried flood sediment — the toxic chemicals, the metals, the biotoxins — is now in the air you breathe into your lungs, potentially affecting your respiratory health.

Buildings needn’t be submerged during flooding to spur respiratory problems. Many homes we studied after Hurricane Ida suffered water intrusion through roofs, windows, and ventilation ducts — and some were more than 100 miles away from coastal regions that bore the brunt of the storm.

The growth of mold can also affect health

Another common hazard is mold, a fungal growth that forms and spreads on damp or decaying organic matter. Indoor mold generally grows due to extensive dampness, and signals a problem with water or moisture. Damp materials inside buildings following a flood create perfect conditions for rapid mold growth.

Mold can be found indoors and outdoors in all climates. It spreads by making tiny spores that float through the air to land in other locations. No indoor space is entirely free from mold spores, but exposure to high concentrations is linked with respiratory complications such as asthma, allergic rhinitis, and sinusitis. Thus, flooding affects respiratory health by increasing the risk of exposure to higher concentrations of mold spores outdoors and indoors.

For example, after Hurricane Katrina in New Orleans in 2005, the average outdoor concentration of mold spores in flooded areas was roughly double that of non-flooded areas, and the highest concentrations of mold spores were measured indoors. A study on the aftermath of Hurricane Katrina and the flooding in the UK in 2007 showed that water damage accelerated mold growth and respiratory allergies.

Children are especially vulnerable to health problems triggered by mold. All respiratory symptoms — including asthma, bronchitis, eye irritation, and cough — occurred more often in homes reporting mold or dampness, according to a study on the respiratory health of young children in 30 Canadian communities. Other research demonstrates that mold contributes to development of asthma in children.

What can you do to protect against the health harms of flooding?

Our research in New Orleans, LA after Hurricane Ida in 2021 identified common factors — both in housing and flooding events — with great impact on respiratory health. Preliminary results suggest two deciding factors in whether substantial indoor mold appeared were the age of a building’s roof and how many precautionary measures people took after flooding from the hurricane. The impact on respiratory health also varied with flood water height, days per week spent at home, and how many precautionary measures were taken after Ida swept through.

Informed by this and other research, we offer the following tips — some to tackle before flooding or heavy rains, and some to take afterward. While you may not be able to entirely prevent flooding from hurricanes or major storms, taking these and other steps can help.

Before seasonal storms, flooding, or heavy rains start: Protect against water intrusion

• Repair the roof, clean gutters, and seal around skylights, vent pipes, and chimneys to prevent leaks. These are some of the most vulnerable components of a building during storms and hurricanes.
• Declutter drains and empty septic tanks.
• Construct barriers and seal cracks in outer walls and around windows, to prevent heavy rain and floodwater from entering.
• Install a sump pump to drain water from the basement, and backflow valves on sewer lines to prevent water from backing up into the home.

After flooding or major rainstorms: Move quickly to reduce dampness and mold growth

The Environmental Protection Agency recommends limiting contact with flood water, which may have electrical hazards and hazardous substances, including raw sewage. Additionally:

• Minimize your stay in flooded regions (particularly after hurricanes) or buildings until they are dry and safe.
• Check building for traces of water intrusion, dampness, and mold growth immediately after flooding.
• Drain floodwater and dispose of remaining sediment.
• Remove affected porous materials. If possible, dry them outdoors under sunlight.
• Increase the ventilation rate by leaving all windows and doors open, or use a large exhaust fan to dry out the building as fast as possible.
• Use dehumidifiers in damp spaces such as basements.
• Upgrade the air filters in your HVAC system to at least MERV 13, or use portable air cleaners with HEPA filters to reduce your exposure to airborne mold spores.

What to do if you spot mold growth

• Wear a well-fitted N95 face mask, gloves, and rubber boots to clean.
• Clean and disinfect anything that has been in contact with water using soap, detergents, and/or antibacterial cleaning products.
• Dispose of moldy materials in sealed heavy-duty plastic bags.

Taking steps like these — before and after a major storm — goes a long way toward protecting your respiratory health.

Read Flooding Brings Deep Trouble in Harvard Medicine magazine to learn more about the health hazards related to floods.

About the Authors

Parham Azimi, PhD, Contributor

Dr. Parham Azimi is a research associate in the department of environmental health at the Harvard T.H. Chan School of Public Health, investigating the indoor environment’s impact on occupant health and wellness and strategies to improve … See Full Bio View all posts by Parham Azimi, PhD

Joseph Allen, DSc, MPH, CIH, Contributor

Dr. Joseph Allen is an associate professor in the department of environmental health at the Harvard T.H. Chan School of Public Health, and the director of Harvard’s Healthy Buildings Program. He is the coauthor of Healthy … See Full Bio View all posts by Joseph Allen, DSc, MPH, CIH

The first thing to know about ringworm is that there are no worms involved.

This generally harmless skin infection is caused by a fungus. The fungus causes a raised rash usually shaped like a ring, almost as if a worm was curled up under the skin (but again: no worms are involved).

The medical name for ringworm is tinea corporis.

Are there other types of tinea infections?

There are many different kinds of tinea skin infections, named in Latin for the part of the body they affect, such as the

• scalp (tinea capitis)
• groin (tinea cruris)
• feet (tinea pedis)
• body (tinea corporis).

Tinea infections can look a bit different depending on what part of the body they affect, but they are usually pink or red and scaly.

How do you get ringworm?

Tinea infections, particularly ringworm (tinea corporis), are very common. People catch them from other infected people and also from infected animals, particularly dogs and cats. They can also spread from one part of the body to another.

What does ringworm look like?

It usually starts as a pink scaly patch that then spreads out into a ring. The ring (which is not necessarily perfectly round) usually spreads wider with time. It can sometimes be itchy, but most of the time doesn’t cause any discomfort.

There are other rashes that can have a ringlike shape, so it’s always important to check in with your doctor, especially if the ring isn’t scaly. But most ringlike rashes are tinea.

How is ringworm treated?

Luckily, tinea corporis and the other kinds of tinea are very treatable. Most of the time, an antifungal cream does the trick.

When the rash is extensive (which is rare) or doesn’t respond to an antifungal cream (also rare), an antifungal medication can be taken by mouth.

As is the case with many other germs these days, there are some drug-resistant cases of tinea related to overuse of antifungal medications. But the vast majority of fungal infections go away with medication.

What should you do if you think a family member — or a pet — has ringworm?

If you think someone in your family has ringworm, call your doctor. The sooner you get started on treatment, the better.

If someone in the family has been diagnosed with ringworm, make sure that others don’t share clothing, towels, or sheets. Have everyone wash their hands frequently and well.

If your pet has a scaly rash, call the vet. Vacuum the areas your pet frequents, and have everyone wash their hands after touching the pet.

Can you prevent ringworm?

To prevent tinea corporis and other kinds of tinea:

• Keep skin clean and dry.
• Change clothes (particularly socks and underwear) regularly.
• Wash your hands regularly (this helps prevent all sorts of infections).
• If your child plays contact sports, make sure they shower after practice, keep their uniform and gear clean, and don’t share gear with other players.

To learn more about ringworm, visit the website of the Centers for Disease and Prevention.

Follow me on Twitter @drClaire

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

There are warnings just about everywhere you look: The coffee you're about to drink is hot! Construction ahead! This product may contain peanuts!

In many cases, the reasons for these warnings are clear. But sometimes warnings raise more questions than they answer. When I was at the gym recently, these warnings on the exercise bike and treadmill were hard to miss in a bright red font:

• Obtain a medical exam before beginning any exercise program.
• Overexercise may result in serious injury or death.
• If you feel faint, dizzy, or have pain stop exercising immediately.

What exactly did the warning writers mean by "any exercise program"? What constitutes overexercise? Does having any pain anywhere mean you should stop working out?

Finally, I wonder: might these warnings cause unnecessary worry that actually discourages people from exercising?

Is it safe to start exercising without checking with a doctor?

A doctor's approval isn't necessary for most of us. Most people can safely begin a low-intensity exercise program and slowly increase their efforts over time. Choose activities that would allow you to carry on a conversation, such as:

• using light weights that are easy for you to lift
• walking at a leisurely pace
• biking at a leisurely pace (less than 5 mph)
• stretching and balancing activities
• light housework or yard work.

If you're starting at a low fitness level, make small increases in your workout over time. For example, if you start out walking 10 minutes a day, add one minute to your walk every week or two. Once you're walking 20 minutes a day, try picking up the pace a bit.

Who should be careful about exercising?

Of course, exercise is riskier if you have certain health conditions. It makes sense to ask a health care professional to make exercise recommendations if you're concerned about your health or have any of these conditions:

• Coronary artery disease, including symptoms of angina or a previous heart attack. Exercise that's too much too soon could stress the heart and trigger a heart attack or dangerous heart rhythm. Lower-intensity workouts (such as short walks at a comfortable pace) may be preferable, at least until it's clear that you can tolerate more.
• Exercise-induced asthma. Your doctor may recommend inhaled treatment to open up airways in your lungs just before or during exercise.
• Muscle disease, such as a metabolic myopathy. Your doctor may discourage you from engaging in certain exercises, such as sprinting or long-distance running.
• Back pain. Low impact exercise, such as biking or swimming, may be a better choice for people with back pain than higher-impact options, such as jogging or basketball.

If exercise is so good for you, why the warnings?

Let's review possible reasons for certain warnings:

• Having a medical examination before starting an exercise program might uncover a condition that makes exercise risky. The best example is probably coronary artery disease, which could trigger a heart attack during intense exercise. Fortunately, sudden heart problems during exercise are relatively rare (though you might think otherwise based on TV and movies, including an episode from the Sex and the City reboot).
• Overexercise is not a well-defined medical term. But it's true that suddenly exercising at high intensity when you're not used to it might be hazardous.
• Stopping exercise if you're feeling faint or dizzy presumably refers to concerns about severe dehydration or other causes of low blood pressure.
• Warnings about pain could refer to chest pain that might be a sign of heart trouble. Or it could be a warning about a type of severe muscle damage called rhabdomyolysis (which may complicate prolonged or intense exercise).

Of course, it's also possible these warnings have little to do with your health and everything to do with lawyers! That is, the equipment manufacturers might hope these warnings will ward off lawsuits from people who suffer a medical problem while using their equipment.

Are these warnings helpful?

Probably not.

All the warnings, alerts, and cautions in our everyday lives can become background noise. Despite red letters and bold fonts, warnings like these are easily overlooked.

Nor do they add much. My guess is that most people experiencing significant dizziness or pain during a workout will stop what they're doing even without reading a warning label. And serious medical conditions arising during exercise are rather rare, so the impact of warning everyone about them is likely small.

The bottom line

Don't be overly alarmed by alerts slapped on exercise equipment. True, it's best not to drop weights on your foot or exercise way too hard or long. If you are worried about workout risks or have been advised to be especially careful about exercising, it's reasonable to talk about it with your doctor.

But that conversation isn't necessary for most people, including those with well-controlled chronic illness such as high blood pressure, diabetes, or coronary artery disease. In fact, regular exercise helps treat many illnesses.

Exercise is among the most important things you can do to improve your health. And inactivity is a generally a much bigger risk than exercising.

So, if you see warnings on the gym equipment at your next workout, keep this in mind: there are much riskier things to worry about. Like hot coffee.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD